System and Method for Multi-Carrier Network Operation

ABSTRACT

Methods, devices, and systems for multi-carrier network operation are disclosed. In one embodiment, a method of pairing and linking carriers in a multi-carrier network, wherein the multi-carrier network includes a downlink carrier, a first uplink carrier, and a second uplink carrier between a base station and a user equipment (“UE”), comprises receiving a Radio Resource Control (“RRC”) signaling; pairing the first uplink carrier with the downlink carrier using information in the RRC signaling, wherein the information includes the pairing of the downlink carrier with the first uplink carrier; and linking the second uplink carrier with the downlink carrier using information in the RRC signaling, wherein the information includes the linking of the downlink carrier with the second uplink carrier.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Entry under 37 U.S.C. 371 ofPCT/CA2010/001486 filed on Sep. 24, 2010 entitled “SYSTEM AND METHOD FORMULTI-CARRIER NETWORK OPERATION”, which claims priority to andincorporates by reference U.S. Provisional Patent Application No.61/246,052 entitled “SYSTEM AND METHOD FOR MULTI-CARRIER NETWORKOPERATION”, filed on Sep. 25, 2009, and U.S. Provisional PatentApplication No. 61/329,906 entitled “SYSTEM AND METHOD FOR MULTI-CARRIERNETWORK OPERATION”, filed on Apr. 30, 2010, the entire contents of whichare hereby incorporated by reference.

BACKGROUND

The present invention relates generally to data transmission incommunication systems and more specifically to methods and systems forfacilitating multi-carrier operation in a mobile communication system.

As used herein, the terms “user equipment” and “UE” can refer towireless devices such as mobile telephones, personal digital assistants(PDAs), handheld or laptop computers, and similar devices or other useragents (“UAs”) that have telecommunications capabilities. In someembodiments, a UE may refer to a mobile, wireless device. The term “UE”may also refer to devices that have similar capabilities but that arenot generally transportable, such as desktop computers, set-top boxes,or network nodes.

In traditional wireless telecommunications systems, transmissionequipment in a base station or other network node transmits signalsthroughout a geographical region known as a cell. As technology hasevolved, more advanced equipment has been introduced that can provideservices that were not possible previously. This advanced equipmentmight include, for example, an evolved universal terrestrial radioaccess network (E-UTRAN) node B (eNB) rather than a base station orother systems and devices that are more highly evolved than theequivalent equipment in a traditional wireless telecommunicationssystem. Such advanced or next generation equipment may be referred toherein as long-term evolution (LTE) equipment, and a packet-basednetwork that uses such equipment can be referred to as an evolved packetsystem (EPS). Additional improvements to LTE systems and equipment willeventually result in an LTE advanced (LTE-A) system. As used herein, thephrase “base station” will refer to any component, such as a traditionalbase station or an LTE or LTE-A base station (including eNBs), that canprovide a UE with access to other components in a telecommunicationssystem.

In mobile communication systems such as the E-UTRAN, a base stationprovides radio access to one or more UEs. The base station comprises apacket scheduler for dynamically scheduling downlink traffic data packettransmissions and allocating uplink traffic data packet transmissionresources among all the UEs communicating with the base station. Thefunctions of the scheduler include, among others, dividing the availableair interface capacity between UEs, deciding the transport channel to beused for each UE's packet data transmissions, and monitoring packetallocation and system load. The scheduler dynamically allocatesresources for Physical Downlink Shared Channel (PDSCH) and PhysicalUplink Shared Channel (PUSCH) data transmissions, and sends schedulinginformation to the UAs through a control channel.

To facilitate communications, a plurality of different communicationchannels are established between a base station and a UE, among otherchannels, a Physical Downlink Control Channel (PDCCH). As the labelimplies, the PDCCH is a channel that allows the base station to sendcontrol signal to a UE for uplink and downlink data communications. Tothis end, the PDCCH is used to transmit scheduling assignment andcontrol data packets referred to as Downlink Control Information (DCI)packets to the UE to indicate scheduling information to be used by theUE to receive downlink communication traffic packets on a PhysicalDownlink Shared Channel (PDSCH) or transmit uplink communication trafficpackets on a Physical Uplink Shared Channel (PUSCH) or specificinstructions to the UE (e.g., power control commands, an order toperform a random access procedure, or a semi-persistent schedulingactivation or deactivation). A separate DCI packet may be transmitted bythe base station to a UE for each traffic packet/sub-frame transmission.

In some cases, carrier aggregation can be used to support widertransmission bandwidths and increase the potential peak data rate forcommunications between a UE, base station and/or other networkcomponents. In carrier aggregation, multiple component carriers areaggregated and may be allocated in a sub-frame to a UE as shown inFIG. 1. FIG. 1 shows carrier aggregation in a communications networkwhere each component carrier has a bandwidth of 20 MHz and the totalsystem bandwidth is 100 MHz. As illustrated, the available bandwidth 100is split into a plurality of carriers 102. UE 10 may receive or transmiton multiple component carriers (up to a total of five carriers 102 inthe example shown in FIG. 1), depending on the UE's capabilities. Insome cases, depending on the network deployment, carrier aggregation mayoccur with carriers 102 located in the same band and/or carriers 102located in different bands. For example, one carrier 102 may be locatedat 2 GHz and a second aggregated carrier 102 may be located at 800 MHz.

In multi-carrier communications network implementations, various typesof carriers can be defined. Backwards compatible carriers includecarriers accessible to UEs that comply to a version or release of thespecification prior to the version of release of the specification inwhich the support of carrier aggregation is added. In other words,backwards compatible carriers are accessible to UEs that are do notsupport and are not aware of carrier aggregation. Such UEs can bereferred to as legacy UEs. For example, if carrier aggregation is addedto LTE release 10, then backwards compatible carriers are accessible toUEs of earlier LTE releases such as LTE release 8 or LTE release 9.Backwards compatible carriers can be operated as a single carrier(stand-alone) or as a part of a carrier aggregation. In the case offrequency division duplexing (FDD) implementations, backwards compatiblecarriers may occur in pairs (e.g., DL (downlink) and UL (uplink) carrierpairs). Non-backwards compatible carriers are not accessible to UEs ofearlier LTE releases, but are accessible to UEs of the LTE release thatdefines the operation of carrier aggregation. Non-backwards compatiblecarriers can be operated as a single carrier (stand-alone) if thenon-backwards compatibility originates from the frequency duplexdistance, or otherwise may be operated as a part of a carrieraggregation. An extension carrier cannot be operated as a single carrier(stand-alone), but must be a part of a component carrier set where atleast one of the carriers in the set is a stand-alone-capable carrier.In multi-carrier networks, a UE DL Component Carrier Set includes theset of DL component carriers on which a UE may be scheduled to receivethe PDSCH in the DL. Similarly, a UE UL Component Carrier Set includesthe set of UL component carriers on which a UE may be scheduled totransmit the PUSCH in the UL.

Of the various carriers in a multi-carrier system, the carriers maygenerally be allocated into one of two types. Type A carriers are fullyconfigured carriers that include all the sync channels and systeminformation broadcasts necessary to allow all UEs to camp includinglegacy UEs and UEs that support or are aware of carrier aggregation. AType A carrier is a backward compatible carrier if it supports legacyUEs. A Type A carrier is a non-backward compatible if it only supportsUEs that support or aware of carrier aggregation. Type B carriers maynot provide all the necessary system information broadcasts and may ormay not include the sync channels. Type B carriers do not allowidle-mode UEs to camp. Similar to the extension carrier, Type B carriersmay only serve RRC_CONNECTED UEs in carrier aggregation mode, i.e., aType B carrier may not be a stand-alone carrier. Finally, Type Bcarriers may or may not include a PDCCH.

FIG. 2 is an illustration of an example network 50 that uses carrieraggregation. In FIG. 2, two base stations 52 and 54 (e.g., eNBs)communicate with several UEs. In this example, each of base stations 52and 54 control 3 ‘cells’. In this illustration, the term cell may beused to refer to a certain geographical coverage area (although itshould be noted that there may be small differences in coverage providedby the different carrier frequencies due to different propagationcharacteristics of the different frequencies). Cells A, B, C and D eachoperate using 3 different carrier frequencies 1, 2 and 3 and eachcarrier frequency further corresponding to a component carrier. Cell Eoperates using 2 different carrier frequencies and cell F operates usinga single carrier frequency. The carrier frequencies used by each ‘cell’depend on the deployment of the network and may be staticallyconfigured, or change infrequently. In the example, UEs 56 and 58 areboth capable of operating using carrier aggregation. UE 58 is locatedwithin cell A and, as such, base station 52 may choose to use up to 3carrier frequencies to communicate with UE 58. In contrast, UE 56 islocated within cell F. Because cell F only provides a single carrierfrequency, base station 54 communicates with UE 56 via a single carrierfrequency only (e.g., carrier frequency 3).

FIG. 3 is an illustration of a multi-carrier network implementation andshows 4 component carriers (Frequencies 1-4) operated by the same basestation (e.g., an eNB). As illustrated, the component carriers are notall adjacent in frequency and may even reside in different radiofrequency bands. In this example, frequencies 1, 2 and 3 are Type Acarriers, while frequency 4 is a Type B carrier. In this example, thebase station has configured UE 60 to operate with frequency 3 as theUE's anchor carrier and frequency 4 as a non-anchor carrier of the UE.UE 62 is configured to operate with frequency 1 as the UE's anchorcarrier and frequencies 2 and 3 as non-anchor carriers. Duringoperation, the base station may reconfigure any of the UEs to change theanchor and non-anchor carriers upon which the UEs are operating (i.e.,there may be a dynamic association between the UE and the carriers onwhich the UE is operating). In this example, UE 64 represents a UE thatis not capable of operating in carrier aggregation mode. For example, UE64 may be a UE that was built to an earlier version of the specificationprior to the introduction of carrier aggregation. As such, UE 64 isconfigured to only operate using frequency 2.

In the example shown in FIG. 3, communication of user data and/or layer3 control signaling (e.g., dedicated radio resource control (RRC)signaling) between the base station and UE 60 may use the anchor carrier(freq 3), the non anchor carrier (freq 4), or both. This behavior may beadjusted based upon the decisions of the scheduler within the basestation.

Generally, in existing multi-carrier communications networkimplementations, although many different categories of componentcarriers (CCs) may be defined, the detailed operation of how a UE isassigned one or multiple of the CCs, the relationship across themultiple CCs and a UE, and the details of a downlink/uplink (DL/UL) CCset for a particular UE are not defined. Additional issues to beconsidered in-carrier aggregation implementations include whether a CCis qualified as a cell. Also, if a CC is qualified as a cell, theappropriate operation when a UE is assigned multiple CCs is undefined.Similarly, in multi-carrier implementations, existing standards fail todescribe how the assignment and activation of a CC to a UE is performed,how a UE switches from one CC to another, how to define the CCs assignedto a particular UE, and how to scramble the data and control channels oneach of the CCs assigned to the UE. Similarly, existing multi-carriernetwork implementations fail to provide mechanisms allowing a legacy UEto distinguish a non-backward compatible carrier from a backwardcompatible carrier.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 shows carrier aggregation in a communications network where eachcomponent carrier has a bandwidth of 20 MHz and the total systembandwidth is 100 MHz;

FIG. 2 is an illustration of an example network that implements carrieraggregation;

FIG. 3 is an illustration of a multi-carrier network implementation andshows 4 component carriers operated by the same base station (e.g., aneNB);

FIG. 4 is a flowchart illustrating a process for a user equipment (UE)to retrieve up-to-date system information (SI) for a component carrier(CC) recently assigned to a UE;

FIG. 5 illustrates a control channel implementation where a single PDCCHmay allocate resources on one or more CCs;

FIG. 6 is a diagram of a wireless communications system including a UEoperable for some of the various embodiments of the disclosure;

FIG. 7 is a block diagram of a UA operable for some of the variousembodiments of the disclosure;

FIG. 8 is a diagram of a software environment that may be implemented ona UA operable for some of the various embodiments of the disclosure; and

FIG. 9 is an illustrative general purpose computer system suitable forsome of the various embodiments of the disclosure; and

FIGS. 10 and 11 are illustrations of example Component Carrier ControlMAC control elements.

DETAILED DESCRIPTION

The present invention relates generally to data transmission incommunication systems and more specifically to methods and systems forfacilitating multi-carrier operation in a mobile communication system.

To this end, some embodiments include a method for receiving a systeminformation (SI) update for at least one of a first component carrier(CC) and a second CC. The first and second CC are provided by a basestation. The method includes receiving a paging message using the firstCC. When the paging message contains a change notification, the methodincludes retrieving CC identification information from the pagingmessage. The CC identification information identifies the second CC. Themethod includes receiving a system information block type 1 (SIB1) usingthe second CC. The SIB1 contains SI scheduling information for thesecond CC. The SI scheduling information defines a modificationboundary. The method includes, during a subframe following themodification boundary, receiving an SIB2 using the second CC.

Other embodiments include a method for receiving a system information(SI) update for a first component carrier (CC). The first CC is providedby a base station. The method includes receiving a radio resourcecontrol (RRC) message from the base station, the RRC message identifyinga paging occasion of the first CC. The method includes, during thepaging occasion, receiving a paging message using the first CC, and,when the paging message contains a change notification, receiving atleast one of a System Information Block Type 1 (SIB1) and a SystemInformation Block Type 2 (SIB2) using the first CC.

Other embodiments include a method for transmitting a system information(SI) update for at least one of a first component carrier (CC) and asecond CC. The first and second CC are provided by a base station. Themethod includes detecting an SI modification for the second CC, andtransmitting a paging message using the first CC. The paging messageincludes a change notification and identification information of thesecond CC. The method includes transmitting a System Information BlockType 1 (SIB1) using the second CC. The SIB1 contains SI schedulinginformation for the second CC and the SI scheduling information definesa modification boundary. The method includes, during a subframefollowing the modification boundary, transmitting an SIB2 using thesecond CC.

Other embodiments include a method for receiving a system information(SI) update for at least one of a first component carrier (CC) and asecond CC. The first and second CC are provided by a base station. Themethod includes receiving a paging message using the first CC. When thepaging message contains a change notification the method includesretrieving identification information from the paging message. Theidentification information identifies the second CC. The method includesreceiving first SI using the second CC. The first SI contains SIscheduling information for the second CC and the SI schedulinginformation defines a modification boundary. The method includes, duringa subframe following the modification boundary, receiving second SIusing the second CC.

Other embodiments include a method for receiving a component carrier(CC) allocation using a user equipment (UE). The method includesreceiving a CC assignment from a base station, the CC assignmentidentifying a first CC provided by the base station. When the CCassignment includes an instruction to enable reception on the first CC,the method includes enabling signal reception on the first CC. When theCC assignment does not include an instruction to enable reception on thefirst CC, the method includes storing system information (SI) of thefirst CC, receiving a second transmission from the base station, thesecond transmission including an instruction to enable reception on thefirst CC, and using the stored SI to enable signal reception on thefirst CC.

Other embodiments include a method for receiving a component carrier(CC) allocation using a user equipment (UE). The method includesreceiving a CC assignment from a base station, the CC assignmentidentifying a first CC provided by the base station. When the CCassignment does not include an instruction to enable reception on thefirst CC, the method includes receiving a second transmission from thebase station, the second transmission including an instruction to enablereception on the first CC, and using system information (SI) of thefirst CC to enable signal reception on the first CC.

Other embodiments include a method for implementing channel scramblingin a multi-carrier network. The multi-carrier network includes a firstcomponent carrier (CC) and a second CC provided by a base station. Thefirst CC has a cell identification (ID) and a Cell Radio NetworkTemporary Identifier (C-RNTI). The method includes receiving a virtualC-RNTI and a virtual cell ID from the base station, and using thevirtual C-RNTI and the virtual cell ID to implement scrambling on thesecond CC.

Other embodiments include a method for implementing channel scramblingin a multi-carrier network. The multi-carrier network includes a firstcomponent carrier (CC) and a second CC provided by a base station. Thefirst CC has a cell identification (ID) and a Cell Radio NetworkTemporary Identifier (C-RNTI). The method includes receiving controlinformation using the first CC, the control information allocating aresource on the second CC, using the cell ID and C-RNTI of the first CCto generate a scrambling sequence, using the scrambling sequence todecode the control information received using the first CC, and usingthe resource allocated by the control information on the second CC.

Other embodiments include a method for implementing channel scramblingin a multi-carrier network. The multi-carrier network includes a firstcomponent carrier (CC) and a second CC provided by a base station. Thefirst CC has a cell identification (ID) and a Cell Radio NetworkTemporary Identifier (C-RNTI). The method includes receiving controlinformation using the first CC. When the control information allocates aresource on the first CC, the method includes using the cell ID and theC-RNTI of the first CC to generate a scrambling sequence for decodingthe control information received using the first CC. When the controlinformation allocates a resource on the second CC, the method includesusing a virtual cell identification (ID) and a virtual Cell RadioNetwork Temporary Identifier (C-RNTI) of the second CC to generate ascrambling sequence for decoding the control information received usingthe first CC.

Other embodiments include a method for implementing channel scramblingin a multi-carrier network. The multi-carrier network includes a firstcomponent carrier (CC) and a second CC provided by a base station. Themethod includes receiving control information using the first CC, andperforming blind decoding to decode the control information using atleast one of a cell identification (ID) and a Cell Radio NetworkTemporary Identifier (C-RNTI) of the first CC and at least one of avirtual cell identification (ID) and a virtual Cell Radio NetworkTemporary Identifier (C-RNTI) of the second CC. When the controlinformation is decoded using a first scrambling sequence generated usingthe cell ID and C-RNTI of the first CC, the method includes using aresource allocated by the control information on the first CC. When thecontrol information is decoded using a second scrambling sequencegenerated using the virtual cell ID and virtual C-RNTI of the second CC,the method includes using a resource allocated by the controlinformation on the second CC.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described. The followingdescription and the annexed drawings set forth in detail certainillustrative aspects of the invention. However, these aspects areindicative of but a few of the various ways in which the principles ofthe invention can be employed. Other aspects and novel features of theinvention will become apparent from the following detailed descriptionof the invention when considered in conjunction with the drawings.

The various aspects of the subject invention are now described withreference to the annexed drawings, wherein like numerals refer to likeor corresponding elements throughout. It should be understood, however,that the drawings and detailed description relating thereto are notintended to limit the claimed subject matter to the particular formdisclosed. Rather, the intention is to cover all modifications,equivalents, and alternatives falling within the spirit and scope of theclaimed subject matter.

As used herein, the terms “component,” “system” and the like areintended to refer to a computer-related entity, either hardware, acombination of hardware and software, software, or software inexecution. For example, a component may be, but is not limited to being,a process running on a processor, a processor, an object, an executable,a thread of execution, a program, and/or a computer. By way ofillustration, both an application running on a computer and the computercan be a component. One or more components may reside within a processand/or thread of execution and a component may be localized on onecomputer and/or distributed between two or more computers.

The word “exemplary” is used herein to mean serving as an example,instance, or illustration. Any aspect or design described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs.

Furthermore, the disclosed subject matter may be implemented as asystem, method, apparatus, or article of manufacture using standardprogramming and/or engineering techniques to produce software, firmware,hardware, or any combination thereof to control a computer or processorbased device to implement aspects detailed herein. The term “article ofmanufacture” (or alternatively, “computer program product”) as usedherein is intended to encompass a computer program accessible from anycomputer-readable device, carrier, or media. For example, computerreadable media can include but are not limited to magnetic storagedevices (e.g., hard disk, floppy disk, magnetic strips . . . ), opticaldisks (e.g., compact disk (CD), digital versatile disk (DVD) . . . ),smart cards, and flash memory devices (e.g., card, stick). Additionallyit should be appreciated that a carrier wave can be employed to carrycomputer-readable electronic data such as those used in transmitting andreceiving electronic mail or in accessing a network such as the Internetor a local area network (LAN). Of course, those skilled in the art willrecognize many modifications may be made to this configuration withoutdeparting from the scope or spirit of the claimed subject matter.

In network implementations, carrier aggregation can be used to supportwider transmission bandwidths and increase the potential peak data ratefor communications between a UE, base station and/or other networkcomponents. In carrier aggregation, multiple component carriers areaggregated and may be allocated in a sub-frame.

Multi-carrier network implementations may be implemented using Type A orType B carriers, or a combination thereof. Generally, because each TypeA carrier is fully configured, a Type A carrier that is backwardcompatible may be accessible to Rel-8, 9, and 10 UEs. In contrast, anon-backward compatible Type A carrier may be accessible only to Rel-10UEs. Each Type A carrier may be configured to operate as a standalonecarrier for both single carrier UEs and multi-carrier UEs.

Generally, within any network, a cell is defined in accordance withRel-8 specifications. Accordingly, from a base station perspective, eachType A carrier supported by the base station may be considered a cell.For example, a base station supporting multiple Type A carriers hasmultiple cells that correspond to each of the Type A carriers.Conversely, Type B carriers may not be defined as cells because thosecarriers are not standalone and are not fully accessible to a UE. Assuch, in the present system, while in an RRC_CONNECTED state, a UE mustbe assigned at least one Type A component carrier (CC) (i.e., a cell)and may be assigned zero or more Type B CCs. In the present disclosure,the term carrier and CC are equivalent and may be used interchangeably.

Anchor Carriers in Multi-Carrier Network Implementations

In some existing network implementations, one of the two cells or CCsassigned to the UE may be designated as a serving cell or anchor CCwhile the other cell or CC is designated as a secondary serving cell.For LTE-A carrier aggregation, because there are two types of carriersand only Type A CCs qualify as cells, one of the assigned Type A CCs maybe designated as an anchor carrier or serving cell of the UE. Thefollowing discussion illustrates one potential implementation of ananchor carrier as deployed in a multi-carrier wireless communicationsystem. The present system provides mechanisms for implementingencryption key derivation algorithms and methods, received signalmeasurements, time/frequency tracking, and monitoring of systeminformation (SI) broadcasts using the anchor carrier of the presentdisclosure.

When communicating with the network using carrier aggregation, one ormore of the communications transmitted via the CCs may be encryptedusing security keys that are different for each CC. In the case of LTE-Acarrier aggregation (CA), because a UE may be assigned multiple CCs onwhich signaling and data information is transmitted, the UE may need tobe configured to define the input parameters to the security keysgeneration algorithms. The security keys are used for encryption andintegrity protection of the signaling and data information. In thepresent system, the UE and the base station may be configured togenerate security key K_(eNB) based on the physical cell identify (PCI)and CC frequency of the anchor carrier assigned to the UE. When a newanchor CC (or target cell) is assigned to the UE (e.g., when the UEswitches from one anchor CC to another), a new security key K_(eNB)* isgenerated based on the existing K_(eNB) and the physical cell identity(PCI) and carrier frequency of the new (or target) anchor CC. In thatcase, the hierarchical keys structure and derivation algorithms asdefined in 3GPP TS 33.401, v9.0.0 can be used. The subsequent keys foruser plane (UP) traffic encryption (K_(UPenc)), RRC traffic encryption(K_(RRCenc)) and RRC traffic integrity protection (K_(RRCint)) may thenbe derived from K_(eNB) or K_(eNB)*.

Alternatively, a UE may be assigned a particular CC by the serving basestation via signaling (e.g., RRC signaling) for encryption and integrityprotection key generation. For example, the UE may be assigned asecurity-anchor CC, upon which security key generation may be based. TheUE may be assigned a security-anchor CC when the UE enters theRRC_CONNECTED state. The UE may then calculate the new K_(eNB) based onthe existing K_(eNB) (e.g., the one derived from K_(ASME) when the UEfirst enters an RRC_CONNECTED state) and the PCI and carrier frequencyof the security-anchor CC. In some embodiments, the security anchor CCmay be semi-statically configured but may be reconfigured by the basestation,

The serving base station may be configured to signal the UE to changethe security-anchor CC during the RRC_CONNECTED state, during handoverto a new base station (e.g., an eNB) and/or during anchor CC switching,for example. The security-anchor CC may be the current anchor CC of theUE or it may be another Type A CC within the UE's Active CC set. In oneimplementation, the security-anchor CC may be any one of the Type A CCsthat serves the same geographical or coverage area of a cell or CC. Asin the case of DC-HSPA, in LTE-A CA, multiple CCs may have the samecoverage area if they belong to the same sector. Once assigned, thesecurity-anchor CC may be fixed for the UE as long as the UE switchesthe UE's anchor CC amongst any Type A CCs that serve the samegeographical area. In an alternative implementation, once assigned, thesecurity-anchor CC may be fixed for the UE as long as the UE continuesto be assigned an anchor CC from within the same base station. The sameset of keys (e.g., K_(UPenc), K_(RRCenc), K_(RRCint)) generated based onthe anchor CC or security-anchor CC may be used for UP traffic and RRCtraffic transmitted on the different CCs assigned to the UE (becauseciphering and integrity protection occur at the packet data convergenceprotocol (PDCP) sublayer, the UP traffic and RRC traffic should beunaware of the CCs that have been assigned to the UE).

When communicating with the network, the UE may be configured to monitora received power and received quality for one or more of the CCs used bythe UE. In the present system, it is not necessary for the UE to reportReference Signal Received Power (RSRP) measurements on each of the CCsbecause the RSRP (which represents the received signal strength) for CCswithin the same band may generally be the same. As such, the anchor CCof a UE may be defined as the carrier upon which RSRP measurements aremade at the UE and reported to the base station. Those measurements mayrepresent the RSRP for all other CCs assigned to the UE in the sameband.

In the case of Reference Signal Received Quality (RSRQ) measurements,because RSRQ represents the signal-to-interference ratio of a CC,different CCs may have different interference levels as a result ofloading conditions, frequency reuse, etc. Therefore, in some cases, RSRQmay be reported by the UE on each of the assigned CCs. RSRQ may also bemeasured and reported on the anchor CC only and represent the RSRQ forall other CCs assigned to the UE in the same band, as in the case ofRSRP described above. For CCs in different bands, the base station mayinstruct the UE to measure and report the RSRP, and possibly RSRQ, ofone of the CCs within each band. Alternatively, only a single RSRQreport may be required for some or all of the CCs assigned to the UE.Also, the base station may configure the UE to measure and report theRSRQ on specific CCs. In another implementation, the base station mayconfigure the UE to report the RSRQ of one of the assigned CCs in a bandand report the delta interference levels of other assigned CCs withinthe same band with respect to the interference level of the carrier forwhich RSRQ is reported. As such, the base station may compute theeffective RSRQ of other assigned CCs based on the RSRQ of the carrierfor which RSRQ is reported plus the delta interference levels reportedby the UE.

In the present multi-carrier system, a UE may be assigned multiple CCs.If the CCs are within the same band, there may not be a need to performsynchronization and time/frequency tracking on all the assigned CCsbecause the CCs are already synchronized amongst each other as theyreside in the same band. As such, the anchor CC of a UE may be the CCupon which the UE performs synchronization and time/frequency tracking.Alternatively, depending upon the base station configuration (e.g.,whether the same clock is applied to all the CCs), the base station mayinstruct the UE to perform synchronization and time/frequency trackingon other non-anchor Type A CCs. The other non-anchor CCs may be CCs inthe same band or in different bands than the anchor CC.

In conventional network implementations, while in an RRC_CONNECTEDstate, a UE may monitor all the necessary system information (SI), i.e.,Master Information Block (MIB), System Information Block Type 1 (SIB1)and System Information Block Type 2 (SIB2) on a single assigned CC. Inthe present system, however, the UE may not continuously monitor MIB,SIB1 and SIB2 on all the assigned CCs because some of the informationmay not change dynamically and some information is not relevant to theUE if the CC is not the anchor CC of the UE. As such, the UE may beconfigured to only monitor MIB, SIB1 and SIB2 on the anchor CCcontinuously. In that case, the base station may be configured toindicate to the UE when to monitor the SI on the other, non-anchorcarriers. The UE may also be configured to monitor paging messages onthe anchor carrier for Earthquake and Tsunami Warning System (ETWS) orPublic Warning System (PWS) notifications and SI change indications, forexample. The paging message sent on the anchor carrier may then be usedto indicate whether the SI in the other CCs assigned to the UE willchange at the next modification period boundary.

In the present system, a UE may be configured to monitor the PDCCH ofone or more of the CCs assigned to the UE. Accordingly, from thephysical layer perspective, one or more of the downlink (DL) CCsassigned to the UE can be designated as PDCCH monitoring CCs. A PDCCHmonitoring CC may be defined as a DL CC where the UE monitors the PDCCHof the CC for PDSCH assignments on at least one of the CC, other DLnon-PDCCH monitoring CCs, and/or other DL PDCCH monitoring CCs. A PDCCHmonitoring CC may also be a DL CC where the UE monitors the PDCCH forPUSCH assignment on the UE's uplink (UL) CCs associated with the DLPDCCH monitoring CC.

In one implementation, a PDCCH monitoring CC is associated with a subsetof the DL non-PDCCH monitoring CCs and/or a subset of DL PDCCHmonitoring CCs where the PDSCH assignment on these CCs is sent on thePDCCH monitoring CC. In another implementation, a PDCCH monitoring CC isassociated with a subset of the UL CCs where the PUSCH assignment onthese CCs in sent on the PDCCH monitoring CC. The set of PDCCHmonitoring CCs may be signaled by the base station to the UE using amedia access control (MAC) control element or RRC signaling, forexample. The association of other DL and UL CCs with each PDCCHmonitoring CC may also be signaled by the base station to the UE throughdedicated signaling such as MAC control element or RRC signaling.Alternatively, the PDCCH monitoring CCs and the association of otherDL/UL CCs with each PDCCH monitoring CC are common to all UEs served bythe same base station within the same geographical area. In that case,the signaling of such information may be sent through broadcastsignaling, such as an SI broadcast.

Each DL or UL CC associated with a PDCCH monitoring CC may be assignedan index corresponding to the PDCCH monitoring CC. The index can be usedin the explicit or implicit CC indication in the PDCCH sent on the PDCCHmonitoring CC to uniquely identify the PDSCH/PUSCH assignment on a DL/ULCC associated with the PDCCH monitoring CC. Generally, an anchor CC willbe one of the PDCCH monitoring CCs. On the other hand, a PDCCHmonitoring CC may not be an anchor CC of the UE. A PDCCH monitoring CCis a Type A CC. In another implementation, however, a PDCCH monitoringCC can be a Type B CC if a Type B transmits a PDCCH. A non-anchor CC mayor may not be a PDCCH monitoring CC.

Non-Anchor Carriers in Multi-Carrier Network Implementations

In a multi-carrier network implementation, CCs other than the anchor CCassigned to a UE may be referred to as non-anchor CCs. The non-anchorCCs that are assigned to the UE can be viewed in two different ways.First, the non-anchor CCs may be viewed as additional or supplementalresources accessible to the UE. Secondly, if the non-anchor CCs are TypeA CCs, the non-anchor CCs may be viewed as secondary or supplementalserving cells accessible to the UE. If the non-anchor CCs are Type BCCs, the non-anchor CCs may be viewed as virtual secondary orsupplemental serving cells of the UE. The following disclosure presentsvarious implementations of non-anchor CCs that are applicable tonon-anchor CCs whether of the first or second type.

In some conventional network implementations, cell specific scrambling,where the scrambling sequence used for traffic and/or control channelsfor each cell is related to the physical cell ID (PCI) of the cell, isimplemented to provide the transmitted signal with more randomcharacteristics improving the signal to noise ratio of the network. Inthe present system, cell specific scrambling of the traffic and/orcontrol channel transmitted on an anchor CC may be implemented using thePCI of the anchor CC. However, for the non-anchor CC the scramblingsequence used for traffic and/or control channels transmission on thenon-anchor CC may be based on the PCI of the anchor CC. In the case of aType A non-anchor CC, the CC may have its own PCI and the scramblingsequence applied may be based on that PCI. In the case of a Type Bnon-anchor CC, the non-anchor CC may not transmit SynchronizationSignals (Primary Synchronization Signal (PSS) and SecondarySynchronization Signal (SSS)) from which the PCI is derived andtherefore a PCI may not exist in the Type B CC. Accordingly, a virtualPCI may be assigned to a Type B CC. The base station can signal thevirtual PCI of a Type B CC to the UE via appropriate signaling (e.g.,RRC signaling). In one embodiment, the RRC signaling sent from the basestation to the UE to assign the virtual PCI is broadcast signaling suchas system information broadcast. In another embodiment, the virtual PCIassignment can be sent from the base station to the UE using dedicatedsignaling as part the Type B CC assignment signaling.

In the present disclosure, when communicating using a non-anchor CC a UEmay not fully implement one or more operations as would be done on ananchor CC to facilitate the operation of a multi-carrier communicationnetwork. For example, when allocated a resource on a non-anchor CC, theUE may not use the PCI and carrier frequency of a non-anchor CC togenerate the security keys for UP and RRC traffic. Similarly, the UE maynot perform synchronization and time/frequency tracking on a non-anchorCC. For example, the UE may only perform synchronization andtime/frequency tracking on a non-anchor CC that is located at a separatefrequency band than the anchor CC. In one implementation, where the TypeB CC does not transmit synchronization signals, when the base stationassigns a Type B non-anchor CC to a UE on a particular frequency band,the base station may also assign a Type A CC to the UE on the samefrequency band. As such, the UE may use the assigned Type A CC forsynchronization purposes. The non-anchor CC may be a Type A CC or a TypeB CC.

When allocated one or more CCs, a UE may be configured to receive systeminformation (SI) broadcasts via all CCs, or a subset of the CCs todiscover certain configuration details for a particular CC. For example,the UE may need to know the physical channel configuration informationof the CC to correctly receive and transmit on various physical channelssuch as the Physical Hybrid ARQ Indicator Channel (PHICH), PhysicalDownlink Control Channel (PDCCH), Physical Random Access Channel(PRACH), Physical Downlink Shared Channel (PDSCH), Physical UplinkShared Channel (PUSCH), and Physical Uplink Control Channel (PUCCH).Also, it is possible for the configuration information to be changed orreconfigured by the base station, for example to adapt to changes in thecell loading. As such, it can be important for the UE to monitor and beaware of any changes made to the SI on the CCs allocated to the UE.

The SI messages may include a MIB plus a number of System InformationBlocks (SIBs). The MIB may contain the PHICH configuration informationthat allows the UE to decode additional information received via thecarrier. The majority of the physical channel configuration informationis contained in SIB2 messages.

Generally, a base station may only make changes to the content of acarrier's SI at the boundary of a specific time duration called amodification period. If there is a change in the content of the SI, thebase station sends paging messages that contain a ‘system informationchange indicator’ during the modification period prior to themodification period at which the change will occur. At the boundarybetween the two modification periods, the base station may increment a‘value tag’ that is contained in a SIB1 message. A UE that is in idlemode monitors the paging channel and, if a paging message containing the‘system information change indicator’ is received, then the UE re-readsthe SI after the next modification period boundary to acquire thechanges to the content.

The paging channel can be transmitted at specific periodically occurringpaging occasions where the location of the paging occasions (i.e., theframe numbers and subframe where the paging occurs) are determined byparameters that are contained in SIB2. An idle mode UE may only monitorone paging occasion every paging cycle. A UE that is in connected modecan either monitor the paging channel periodically for paging messagescontaining the ‘system information change indicator’, or the UE canre-read the ‘value tag’ from the SIB1 message after each modificationperiod boundary to detect a change in the content of system information.Upon detecting any changes, the UE may re-read the SI to acquire thechanges. In addition, some SI content, in particular the physicalchannel configuration information from an SIB2 message, can also beincluded in dedicated RRC messages (i.e., RRC messages that are sent toor from a specific UE) that command the UE to perform a handover toanother cell or CC, thus allowing the UE to start communicating withthat CC without any delay associated with reading the SI.

In the present system, for carrier aggregation, the UE may use existingmechanisms to obtain the necessary system or configuration informationdescribing the anchor CC. However, to obtain SI describing thenon-anchor CCs new mechanisms are needed. In the present systemalternative mechanisms are presented depending upon whether thenon-anchor CC is a Type A CC or a Type B CC.

If the non-anchor CC is a Type A CC then the non-anchor CC may broadcastSI. Some SI that may be broadcast from the non-anchor CC may not berelevant to the UE and can be ignored—the information may be relevant toUEs for which this CC is the UE's anchor CC or for UEs that are campedin idle mode on the CC. An example of such information is the TrackingArea Identity (TAI) or Cell Global Identity (CGI). Such animplementation would not place any requirements on the network tocoordinate or align this information between the component CCs; it wouldstill be possible for the network to use different TAIs and CGIs on thedifferent component CCs.

In the present system, the PHICH configuration information of thenon-anchor CCs needs to be conveyed to a UE who has been assigned thosecarriers. In one implementation, the UE may decode the MIB on thenon-anchor CC periodically on the subframe where the MIB is transmitted.Alternatively, the PHICH configuration of a non-anchor CC can be sent tothe UE using dedicated signaling (e.g., RRC signaling). The PHICHconfiguration information may only need to be sent to the UE when theconfiguration has changed or is about to change. In one implementation,the base station sends dedicated RRC signaling or MAC control element tothe UE to convey the updated PHICH configuration information of anon-anchor CC assigned to the UE. In one implementation, the dedicatedRRC signaling or MAC control element is sent on any of the active CCsassigned to the UE. In another implementation, the dedicated RRCsignaling or MAC control element is sent on any of the active CCsassigned to the UE, except the non-anchor CC for which the PHICHconfiguration information is targeted. In another implementation, thebase station sends multicast signaling, such as MAC signaling or RRCsignaling, on a Type A CC to convey the updated PHICH configurationinformation to a group of UEs whose anchor CC is this Type A CC and whohave been assigned the non-anchor CC. A group Radio Network TemporaryIdentifier (RNTI) may be used to address the group of UEs that have beenassigned to a non-anchor CC and this group RNTI may be provided to theUE using the RRC signaling used to assign that component carrier to theUE. The group RNTI may then be used for cyclic redundancy check (CRC)masking of the PDCCH and scrambling of the PDSCH used to carry themulticast RRC or MAC signaling. In another implementation, the basestation sends broadcast RRC signaling (e.g., SI) on a Type A CC toconvey the updated PHICH configuration information of a subset or allother Type A and Type B CCs serving the same geographical area. Inanother implementation, the base station sends broadcast RRC signaling,such as SI, on a Type A CC to convey the updated PHICH configurationinformation of other Type A and Type B CCs that could be associated withthe Type A CC.

SIB2 and MIB Information Acquisition by a UE

As described above, other than the PHICH configuration information, amajority of the physical channel configuration information is containedin System Information Block 2 (SIB2) messages.

If a non-anchor CC is not a PDCCH monitoring CC, the UE can be notifiedof the changes in the content of system information (i.e., in someembodiments, referring to MIB and/or SIB2) for the non-anchor carrierthrough the paging messages sent on the anchor CC from the base station.If the paging message indicates that there are some changes at the nextmodification period boundary, the UE may enable PDCCH monitoring on thenon-anchor carrier to read the system information (i.e., in someembodiments, referring to MIB if the paging message indicates thatinformation in MIB will change; and/or SIB1 by enabling PDCCH monitoringon the non-anchor carrier if the paging message indicates that theinformation in SIB2 will change) transmitted by the non-anchor CC afterthe start of the next modification period boundary. The UE obtains SIscheduling information from SIB1. The UE may then enable PDCCHmonitoring on the non-anchor CC at the subframe where SIB2 informationis expected to be broadcast on the non-anchor CC.

By including indications of changes of the MIB and/or SIB2 content ofnon-anchor CCs in the paging messages sent on the anchor CC, the UE canavoid monitoring paging messages on more than one CC. In oneimplementation, at the subframes upon which the UE enabled PDCCHmonitoring to receive SIB1 or SIB2 messages on the non-anchor CC, the UEmay not monitor the PDCCH on the anchor CC or one or more of other PDCCHmonitoring CCs.

If the UE does not monitor the PDCCH on the anchor CC or one or more ofother PDCCH monitoring CCs then there may be some data loss on those CCsand other CCs associated with those CCs. That loss, however, may beacceptable if the frequency of the change of SIB2 content is relativelylow.

The number of carriers upon which the UE can simultaneously decode thePDCCH may be signaled by the UE to the base station (e.g., using RRCsignaling). The base station may then refrain from sending PDCCH to theUE on the anchor CC and/or one or more PDCCH monitoring CCs at thesubframes where the UE monitors the PDCCH on the non-anchor CC which isnot a PDCCH monitoring CC. For example, the base station may signal tothe UE the PDCCH monitoring CCs that will not be in effect while the UEis decoding SIB2 information of a non-anchor CC which is not a PDCCHmonitoring CC. Alternatively, the PDCCH monitoring CCs of an UE that arenot in effect may be predefined, for example, as a number of PDCCHmonitoring CCs starting with the smallest/largest carrier index. In somecases, the UE may be configured to inform the base station when the MIBand/or SIB1 and/or SIB2 information acquisition on a non-anchor CC hasbeen completed. In one implementation, the UE may prioritize the PDCCHblind decoding on the common search space of the PDCCH monitoringcarriers and the common search space of the non-PDCCH monitoringcarriers where SIBs reading is required, over the blind decoding onUE-specific search space of the PDCCH monitoring carriers.

Table 1 is an illustration of a paging message structure that includes asystem information change indication field for each CC to facilitatereceipt of SI messages from a UE via an anchor carrier and one or morenon-anchor carriers. The changes with respect to the paging message ofRel-8 and Rel-9 are underlined.

TABLE 1 -- ASN1START Paging ::= SEQUENCE {   pagingRecordListPagingRecordList OPTIONAL,   -- Need ON   systemInfoModificationENUMERATED {true} OPTIONAL,   -- Need ON   etws-Indication ENUMERATED{true} OPTIONAL,   -- Need ON   nonCriticalExtension SEQUENCE {    carrierSystemInfoModificationList CarrierSystemInfoModificationList  OPTIONAL,     nonCriticalExtension SEQUENCE { } OPTIONAL   -- Need OP  } OPTIONAL -- Need OP } PagingRecordList ::= SEQUENCE (SIZE(1..maxPageRec)) OF PagingRecord PagingRecord ::= SEQUENCE {  ue-Identity PagingUE-Identity,   cn-Domain ENUMERATED {ps, cs},   ...} PagingUE-Identity ::= CHOICE {   s-TMSI S-TMSI,   imsi IMSI,   ... }IMSI ::= SEQUENCE (SIZE (6..21)) OF IMSI-Digit IMSI-Digit::= INTEGER(0..9)CarrierSystemInfoModificationList ::=SEQUENCE (SIZE (1..maxSIModRec)) OFCarrierSystemInfoModification CarrierSystemInfoModification :: =SEQUENCE {   carrier-Index Physical-Carrier-Index,   modificationMIBENUMERATED (true)   modificationSIB2 ENUMERATED (true) } -- ASN1STOP

With reference to Table 1, the following paging field descriptions maybe used. Carrier index is an Index to the carrier to which theCarrierSystemInfoModification applies. ModificationMIB is a true orfalse value that indicates whether the system information in MIB on thecarrier will be changed at the next modification period boundary.ModificationSIB2 refers to a true or false value that indicates whetherthe system information in SIB2 on the carrier will be changed at thenext modification period boundary.

With reference to Table 1, in one implementation of the paging message,the CarrierSystemInfoModification fields for other CCs may be includedin all of the paging occasions. Alternatively, theCarrierSystemInfoModification fields for other CCs are included in onlysome of the paging occasions. By including the extraCarrierSystemInfoModification fields in only a subset of pagingoccasions there may be a reduction in the overhead contained in eachpaging message, both in size and processing requirements. In that case,however, the UE may need additional information describing the pagingoccasions that will contain the CarrierSystemInfoModification fields.Those paging occasions may be fixed or be configurable by the basestation. If configurable, the base station may inform the UE of thepaging occasions that will include the CarrierSystemInfoModificationfields for other CCs. In one implementation, differentCarrierSystemInfoModification fields for different sets of CCs may besent on different paging occasions.

In another implementation, the UE may be configured to decode the pagingmessage on a non-anchor CC to read the system information changeindication for a non-anchor CC. In that case, any paging occasions onthe non-anchor CC that include SI change indications may be defined bythe base station and communicated to the UE (e.g., using RRC signaling).The base station may inform the UE of the radio frames and subframes inwhich the paging occasions will take place. One specific implementationof an RRC message configured to communicate such information is shown inTable 2 below (see, specifically, the variables siPaging-Config1 andsiPaging-Config2 illustrated in the example RRC message forcommunicating the paging configuration for a particular non-anchor CC).

Alternatively, paging occasions on non-anchor carriers can be obtainedin the same manner as that defined for Idle mode in Rel-8 (see Section 7of TS36.304) but applied to a UE in RRC_CONNECTED mode. In oneimplementation, at those paging occasions, the UE enables PDCCHmonitoring on the non-anchor carrier for the common PDCCH search space.The UE decodes the common PDCCH search space on the non-anchor carrierfor Paging RNTI (P-RNTI) and if the UE succeeds in decoding the PDCCHwith the P-RNTI, the UE subsequently decodes any paging message sent onthe non-anchor carrier. In another implementation, the PDCCH sent on ananchor carrier or a PDCCH monitoring carrier is used to indicate PDSCHassignment on the non-anchor carrier that carries paging message of thatcarrier. A carrier indication field (CIF) is added to the DCI (e.g., DCIformat 1A or 1C) whose CRC is scrambled by the P-RNTI. The carrierindicator field (CIF) may indicate to which carrier the DCI corresponds.At the indicated paging occasions, the UE performs blind decoding ofPDCCH in the common PDCCH search space of the anchor carrier or PDCCHmonitoring carrier using the modified DCI formats (e.g., DCI format 1Aand 1C with the inclusion of CIF) and P-RNTI de-scrambling, to read thepaging message sent on the non-anchor carrier indexed by the CIF. Inaddition, the UE may perform blind decoding of the PDCCH in the commonPDCCH search space of the anchor carrier or the PDCCH monitoring carrierusing the regular DCI formats, i.e., without inclusion of CIF field, todecode the PDCCH that carries PDSCH assignment for the anchor carrier orthe PDCCH monitoring carrier itself. The benefit of this approach isthere is no need to include SI change indications or paging occasionsconfiguration for other CCs in a Type A CC. This allows SI to beindependently managed across CCs. The paging occasions that include theSI change indication on the non-anchor CC may occur periodically with aperiod that is a multiple of the paging occasions on the anchor CC, withthe multiple being communicated to the UE via RRC signaling as shown inTable 2. In addition, the paging occasions that include SI changeindications on the non-anchor CC may occur during the same subframes asthose of the anchor CC. Alternatively, the paging occasions for thenon-anchor CC may be a function of the paging occasions for the anchorCC (e.g., at a similar frequency and period, or a multiple of that ofthe anchor CC's paging cycle, but with a configured or predefined radioframe/subframe offset).

In another implementation, the PDCCH sent on the anchor carrier or aPDCCH monitoring carrier is used to indicate the PDSCH assignment on anon-anchor carrier that carries SIBs of that carrier. A CIF is added tothe DCI (e.g., DCI format 1A or 1C) whose CRC is scrambled by theSI-RNTI. If the paging message sent on the anchor carrier or thenon-anchor carrier indicates that there are some changes to the SI ofthe non-anchor carrier at the next modification boundary, at thesubframes where SIB1 is transmitted in the next modification boundary,the UE performs blind decoding of PDCCH in the common PDCCH search spaceof the anchor carrier or a PDCCH monitoring carrier using the modifiedDCI formats (e.g., DCI format 1A and 1C with the inclusion of CIF) andSI-RNTI de-scrambling, to read the SIB1 transmitted on the non-anchorcarrier indexed by the CIF. In addition, the UE may perform blinddecoding of PDCCH in the common PDCCH search space of the anchor carrieror the PDCCH monitoring carrier using the regular DCI formats, i.e.,without inclusion of CIF field, to decode the PDCCH that carries PDSCHassignment for the anchor carrier or the PDCCH monitoring carrieritself.

The UE may obtain SI scheduling information on the non-anchor carrierafter reading the SIB1 on the non-anchor carrier. At the correspondingsubframe(s) where SIB2 is transmitted on the non-anchor carrier, the UEmay perform blind decoding of PDCCH in the common PDCCH search space ofthe anchor carrier or a PDCCH monitoring carrier using the modified DCIformats (e.g., DCI format 1A and 1C with the inclusion of CIF) andSI-RNTI de-scrambling, to read the SIB2 on the non-anchor carrierindexed by the CIF. In addition, the UE may perform blind decoding ofPDCCH in the common PDCCH search space of the anchor carrier or thePDCCH monitoring carrier using the regular DCI formats, i.e. withoutinclusion of CIF field, to decode the PDCCH that carries PDSCHassignment for the anchor carrier or the PDCCH monitoring carrieritself.

Alternatively, rather than using CIF to indicate the non-anchor carrierthat carries the SIBs, the DCI transmitted on the anchor carrier thatassigns PDSCH resources on the non-anchor carrier to carry SIB1 or SIB2may be CRC-scrambled by a specific SI-RNTI associated with thenon-anchor carrier. In that case, there is a unique SI-RNTI valueallocated with each DL carrier. The unique SI-RNTI value can be used forscrambling of CRC when the DCI transmitted by one carrier is used toassign PDSCH resource on another carrier to carry the SI (e.g., SIB1,SIB2) of that carrier. The SI-RNTI value associated with each DL carriercan be predefined in the standards specification or configured by thebase station and signaled to the UE via RRC signaling, e.g. in the RRCsignaling used to assign a DL carrier to the UE.

If the non-anchor CC is a PDCCH monitoring carrier, the UE may decodepaging messages on the anchor CC to receive SI change indications forother non-anchor CCs, as described above. In this implementation,however, although the UE can decode the common PDCCH search space on thenon-anchor CC for System Information Radio Network Temporary Identifiers(SI-RNTI) and the subsequent SIB1 and SIB2 information, by monitoringthe SI change indication sent in the paging message of the anchor CC,the UE does not need to do blind detection of SI-RNTIs on the non-anchorCC. The UE also does not need to decode the MIB and/or SIB1 and/or SIB2on the non-anchor CC if the paging message sent on the anchor CC doesnot indicate a change in the SI of the non-anchor CC. In this manner,the UE's battery power can be saved by reducing the blind decodingamount.

Alternatively, if the non-anchor CC is a PDCCH monitoring carrier, theUE may decode paging messages on the non-anchor CC to receive SI changeindications for the non-anchor CC, as described above. The pagingoccasions on the non-anchor CC that include the SI change indicationscan be defined by the base station and communicated to the UE viasignaling such as RRC signaling. In the RRC signaling message, the radioframes and subframes for the paging occasions may be included. Onespecific implementation of such an RRC message is shown in Table 2 (see,specifically, the variables siPaging-Config1 and siPaging-Config2illustrated in the example RRC message for communicating the pagingconfiguration for a particular non-anchor CC). At those pagingoccasions, the UE can decode the common PDCCH search space on thenon-anchor carrier for Paging RNTI (P-RNTI) and if the UE succeeds indecoding the PDCCH, subsequently decode the paging message sent on thenon-anchor CC. The benefit of this approach is that there is no need toinclude SI change indications for other CCs in a Type A CC. As such, SImay be independently managed across CCs. The paging occasions for SIchange indications on the non-anchor CC may occur periodically, with theperiod being defined as multiples of the period for paging occasions onthe anchor CC. In addition, the paging occasions that include SI changeindications on the non-anchor CC may occur in the same subframe as thatof the anchor CC. Alternatively, the paging occasions for the non-anchorCC may be a function of the paging occasions for the anchor CC (e.g.similar frequency and period, or a multiple of the anchor CC's pagingcycle, but with a configured or predefined subframe offset).

System Information Acquisition by the UE through Either or Both ofPaging Notification on the Anchor Carrier and Dedicated Signaling

In one implementation of the present system, a base station may includeSI change notification for a DL non-anchor carrier and paired ULnon-anchor carrier in a paging message sent on the DL anchor carrier andmay, in some cases, also send dedicated RRC signaling to a UE to informthe UE of the updated SI of the non-anchor DL/UL carrier.

The base station may send the dedicated RRC signaling to the UE toprovide updated SI of a non-anchor DL/UL carrier when the UE is unableto decode (or when the base station expects that the UE will havedifficulty to decode) the SI sent (through MIB, SIB1 and SIB2) on thenon-DL anchor carrier itself. The possible situations where the UE maybe unable to decode the SI sent on the DL non-anchor carrier mayinclude 1) the UE is out of coverage of the DL non-anchor carrier,and/or 2) the UE is experiencing strong inter-cell interference on theDL non-anchor carrier, e.g. in a heterogeneous network scenario. Thebase station may be made aware of such situations through measurementreports (e.g. RSRP and/or RSRQ), and/or CQI reports of the DL non-anchorcarrier from the UE. The base station can configure the UE to sendmeasurement reports when the received signal quality (RSRP/RSRQ) on theDL non-anchor carrier is below certain configured thresholds and/or whenthe received signal quality (RSRP/RSRQ) is above certain configuredthresholds.

In one implementation, the base station indicates to the UE (e.g. viaRRC signaling) whether it should acquire SI on a DL non-anchor carrierwhen the UE receives SI change notification for the DL non-anchorcarrier and paired UL non-anchor carrier in a paging message sent on theDL anchor carrier. In one implementation, if the base station indicatesto the UE it should acquire SI on a DL non-anchor carrier when SI changenotification for the DL non-anchor carrier is received, the eNB maystill transmit dedicated RRC signaling to the UE to convey updated SI ofthe non-anchor carrier to the UE.

The following are procedures that may be executed at a UE to handle SIchange notifications received in paging messages sent on the DL anchorcarrier and updated SI received from dedicated RRC signaling:

First, when the UE receives SI change notification of a non-anchor DL/ULcarrier in the paging message sent on the DL anchor carrier, the UE mayattempts to decode the corresponding SI (i.e., MIB, and/or SIB1 andpossibly SIB2 if the system InfoValueTag in SIB1 indicates that SI hasbeen updated from what is stored in the UE) transmitted on the DLnon-anchor carrier at the next modification period boundary. In somecases, the UE may decode the SI on the DL non-anchor carrier only if theDL non-anchor carrier is active. Alternatively, the UE decodes the SI onthe DL non-anchor carrier if the DL non-anchor carrier is configured. Inanother implementation, the UE decodes the SI on the DL non-anchorcarrier if the linked or paired UL non-anchor carrier is configured.Alternatively, the UE decodes the SI on the DL non-anchor carrier if thelinked or paired UL non-anchor carrier is configured and active.Alternatively, the UE may decode the SI on the DL non-anchor carrierregardless of whether the linked or paired UL non-anchor carrier isconfigured. The UE can update its stored SI of the DL/UL non-anchorcarrier based on the acquired SI.

Second, at any time when the UE receives dedicated RRC signaling fromthe base station with updated SI of a DL/UL non-anchor carrier, the UEcan update its stored SI of the DL/UL non-anchor carrier based on theinformation received.

Third, if the UE has received SI change notification of a DL/ULnon-anchor carrier during modification period N, but has not receivedupdated SI of the DL/UL non-anchor carrier during modification periodN+1, either through self acquisition of MIB, SIB1 and possibly SIB2 senton the DL non-anchor carrier or through dedicated RRC signaling from thebase station, the UE may not transmit on the paired UL non-anchorcarrier.

In one implementation, the base station only sends dedicated RRCsignaling to the UE containing the updated SI of the DL/UL non-anchorcarrier within the corresponding modification period of the DL/ULnon-anchor carrier where the updated SI applies.

In one implementation, when the UE receives a paging message thatincludes SI change indication of a non-anchor carrier, the UE attemptsto acquire the updated SI of the non-anchor carrier at the nextmodification period boundary. After the UE succeeds in receiving the SIof the non-anchor carrier, the UE sends an acknowledgement signaling tothe base station (e.g., eNB), e.g. via RRC signaling. In this way, thebase station knows that the UE has acquired the updated SI of thenon-anchor carrier.

Type B Carriers

In the present system a Type B CC can only operate as a non-anchor CC ofa UE—a Type B CC does not transmit all the system information that wouldbe transmitted by a Type A CC. For example a Type B CC may not transmitinformation such as DL bandwidth, cell related information, or ULcarrier frequency. A Type B CC may or may not transmit synchronizationsignals (which allow for the derivation of PCI).

If the Type B CC does transmit a PDCCH, the CC may also be configured tobroadcast configuration information such as radio resource configurationinformation, and PHICH configuration information. A new SIB type may bedefined for a Type B carrier to carry the radio resource configurationinformation and the PHICH configuration information for a non-anchor CC.The information in the new SIB may be a subset of that provided by aSIB2 message plus the PHICH configuration.

In one implementation, the Type B CC only transmits the new SIB whenthere is an update to the information. In some cases, any updates of theinformation in the new SIB cannot occur more frequently than everymodification period. The Type B CC may only transmit the new SIB atpredefined periods or subframes/radio frames. Whether the transmissionis event-triggered or predefined, the scheduling information of the newSIB on the Type B CC can be predefined or can be signaled to the UE viathe UE's anchor CC. The signaling of the scheduling information can beperformed using RRC signaling messages that include the radio frames andsubframes during which the new SIB may be transmitted on the Type B CC.One specific implementation of such an RRC message is shown in Table 2.For these implementations, similar approaches to signal to the UE the SIchange indication (in this case corresponding to the new SIB) and forthe UE to acquire the SI, i.e. the new SIB, on the non-anchor Type B CCas described above can be implemented.

In the case where the Type B CC does not transmit DL controlinformation, including a PDCCH, PCFICH and PHICH, the UE may not beinformed of the PHICH configuration of the non-anchor CC. In that case,a new SIB type may be defined for Type B CCs that carries only radioresource configuration information. In that case, a Type A CC transmitsa PDCCH with SI-RNTI to point to the PDSCH of the Type B CC that carriesthe new SIB. The UE may then monitor the UE's anchor Type A CC for thePDCCH that points to the PDSCH of any of the other Type B CCs that servethe same geographical area. Alternatively, the UE may monitor any of theassigned Type A PDCCH monitoring carrier for the PDCCH that points tothe PDSCH of other Type B CCs that serve the same geographical area. AType A CC may only transmits a PDCCH to point to the PDSCH of the Type ACC's associated Type B CCs. The Type A CC may be configured to onlytransmit the PDCCH to point to the PDSCH of a Type B CC that carries thenew SIB whenever there is an updated new SIB sent on the Type B CC. A CCindication field may be added to the existing DCI format 1C to indicatethe Type B CC to which the PDSCH assignment corresponds. In anotherimplementation, a new DCI format which includes a CC indication field isintroduced to carry the PDSCH assignment information for a Type B CC.

Alternatively, the Type B CC does not transmit any SI related to radioresource configuration or PHICH configuration. In that case, the UE maybe configured to acquire the SI of a non-anchor Type B CC via its anchorCC—a Type A CC. In one implementation, a Type A CC broadcasts the SI ofall other Type B CCs that serve the same geographical area. This extrainformation on the Type A CC could be encoded within a new SIB messageor could be appended to the existing SIB2 message. In anotherimplementation, a Type A CC only broadcasts the SI of the Type B CCsthat are associated with the Type A CC.

In yet another implementation, the Type B CC transmits DL controlinformation including a PDCCH, Physical Control Format Indicator Channel(PCFICH) and PHICH, but the Type B CC does not transmit PHICHconfiguration information and only transmits the SI related to radioresource configuration. The PHICH configuration and PCFICH informationof a Type B CC (e.g., the number of orthogonal frequency-divisionmultiplexing (OFDM) symbols for PDCCH) may be fixed or preconfigured tothe UE via signaling on the anchor CC or other assigned Type A CCs. Ifthe PHICH configuration and/or PCFICH information is not fixed, the UEmay acquire the information related to PHICH configuration and PCFICH ofits non-anchor Type B CC on the UE's anchor CC or other assigned Type ACCs. In one implementation, a Type A CC broadcasts the PHICHconfiguration and PCFICH information of all other Type B CCs that servethe same geographical area. In another implementation, a Type A CC onlybroadcasts the PHICH configuration and PCFICH information of those TypeB CCs that are associated with the Type A CC. A new SIB type isintroduced for the Type A CC to carry the PHICH configurationinformation and PCFICH information of one or more Type B CC.Alternatively, the PHICH configuration information and PCFICHinformation of one or more Type B CC is appended to the existing SIB(e.g., SIB2) of a Type A CC.

Component Carrier Sets

When a UE initially enters an RRC_CONNECTED state, the UE is generallyassigned a single Type A CC. The CC upon which the UE performs initialaccess may be the first assigned CC of the UE to carry UP traffic andRRC traffic. By default, the CC becomes the anchor CC of the UE. Thebase station may re-assign other Type A CCs to the UE as the anchor CCafter the UE enters the RRC_CONNECTED state. Additional CCs may then beassigned to the UE by the base station. The set of CCs assigned to theUE can be classified into the Candidate CC Set and the Active CC Set.

In the present system, when assigning a CC to a UE, the base station mayalso instruct the UE to enable signal reception on the CC. When a CC isassigned to the UE without requiring the UE to enable signal receptionon the CC, the CC becomes part of the UE's Candidate CC Set but not partof the Active CC Set. When a CC is assigned to the UE, and the UE isrequired to enable signal reception on the CC, the CC becomes part ofthe UE's Candidate CC Set and Active CC Set. A UE's Active CC set istherefore a subset of the UE's Candidate CC Set.

In the case of DRX, during the Active time of a CC, the CC is part ofthe UE's Active CC set. When not in Active time of a CC, the CC is partof the UE's Candidate CC set. When transitioning between Active time andnon Active time is through configured DRX timers and cycles, no explicitsignaling is required to activate/de-activate the CC.

For the CCs within the Active CC set of the UE, the UE needs to know theup-to-date system information (e.g., MIB, SIB1, SIB2) associated witheach CC. FIG. 4 is a flowchart illustrating process 70 for a UE toretrieve up-to-date SI for a CC recently assigned to a UE. The processallows for simple and low-overhead activation of a CC into the UE'sActive CC set.

In step 72, when a CC is assigned to the UE by the base station, thenecessary SI of the CC is provided to the UE via RRC signaling, if suchinformation is not already broadcast by the base station.

In one implementation of the present system, in the first step 72, whena CC is first assigned to the UE, detailed information of the CC is alsosignaled to the UE via dedicated signaling carried on one or multipleCCs in the Active CC set of the UE. The information types may include atleast one of 1) SIB1 related information such as PCI, CGI (for Type Acarrier only), or Closed Subscriber Group (CSG) related information; 2)the assigned DL and/or UL CC frequency and corresponding bandwidths. Inone implementation, if DL CC is assigned, the paired UL CC frequency isprovided regardless of whether the paired UL CC is assigned or active.Alternatively, if DL CC is assigned, the paired UL CC frequency is onlyprovided if the paired UL carrier is also assigned or active. If UL CCis assigned the paired DL CC frequency is also provided; 3) SIB2 relatedinformation for radio resource configuration which can changedynamically; 4) an indication of whether the CC is a Type A or Type BCC; 5) an indication of whether the CC is a PDCCH monitoring CC; 6) ifthe CC is a Type B CC, scheduling information for the SI of the CC; 7) alisting of paging occasions on the CC that includes the SI changeindication; 8) a physical CC index and the mapped logical CC index ofthis CC; 9) if the CC is a Type B CC, the virtual PCI of the CC; and 10)Cell Radio Network Temporary Identifier (C-RNTI) for the UE on this CC,if applicable. For SIB1 and SIB2 information, only information deltasfrom those of the anchor CC may be signaled to the UE. A physical CCindex may be defined by the numbering of the CCs supported by the basestation from the base station perspective. For example, the numberingmay correspond to the CCs supported by the base station sorted inincreasing order of the CC frequency. The logical CC index is definedfrom the UE perspective and may be the index of the CC assigned to theUE. The logical CC index of an assigned CC may be used in subsequentsignaling between the base station and the UE. For example, the logicalCC index may be used in PDCCH grants for PDSCH/PUSCH assignment on theCC or CC indication in MAC control element for activation/de-activationof the CC.

In step 74, if the base station instructed the UE to enable signalreception on the CC in step 72, the CC becomes a member of the Active CCset of the UE. In that case, the UE acquires the up-to-date SI for theCC on an on-going basis as described above.

In step 76, if the base station did not instruct the UE to enable signalreception on the CC, the CC becomes a member of the Candidate CC setrather than a member of the Active CC set for the UE. In that case, theUE stores the SI of CC provided by the base station in step 72. The UEdoes not need to acquire the SI of the CC on an on-going basis.

In step 78, at a pre-determined time, the base station instructs the UEto enable signal reception on a CC within the Candidate CC set. If theSI of the CC has not changed from what is provided in step 72, the basestation may send a short signaling message (e.g., MAC control element orPDCCH) to activate the CC. On the other hand, if the SI of the CC haschanged from that provided in step 72, there are two alternativeapproaches. The base station may send RRC signaling to activate the CCand at the same time provide the up-to-date SI in the RRC signalingmessage. Alternatively, the base station may send a short signalingmessage (e.g., MAC control element or PDCCH) to activate the CC. Afterreceiving the message, the UE acquires the up-to-date SI on the CCindependently.

Table 2 shows example RRC signaling to assign or de-assign a CC to orfrom a UE using dedicated signaling. In the case of CC assignment, theRRC signaling includes the associated CC information described above.The changes with respect to the RadioResourceConfigDedicated InformationElement (IE) of Rel-8 and Rel-9 are underlined

TABLE 2 RadioResourceConfigDedicated The IE RadioResourceConfigDedicatedis used to setup/modify/release RBs, to modify the MAC mainconfiguration, to modify the SPS configuration and to modify dedicatedphysical configuration. RadioResourceConfigDedicated information element-- ASN1START RadioResourceConfigDedicated ::=   SEQUENCE {  srb-ToAddModList   SRB-ToAddModList OPTIONAL, -- Cond HO-Conn  drb-ToAddModList   DRB-ToAddModList OPTIONAL, -- Cond HO-toEUTRA  drb-ToReleaseList   DRB-ToReleaseList OPTIONAL, -- Need ON  mac-MainConfig   CHOICE {       explicitValue     MAC-MainConfig,      defaultValue     NULL   }    OPTIONAL, -- Cond HO-toEUTRA2  sps-Config   SPS-Config OPTIONAL, -- Need ON   physicalConfigDedicated  PhysicalConfigDedicated OPTIONAL, -- Need ON   ...  componentCarrierConfig   ComponentCarrierConfig OPTIONAL -- Need ON }SRB-ToAddModList ::= SEQUENCE (SIZE (1..2)) OF SRB-ToAddMod SRB-ToAddMod::= SEQUENCE {   srb-Identity   INTEGER (1..2),   rlc-Config   CHOICE {    explicitValue     RLC-Config,     defaultValue     NULL  }    OPTIONAL, -- Cond Setup   logicalChannelConfig   CHOICE {    explicitValue     LogicalChannelConfig,     defaultValue     NULL  }    OPTIONAL, -- Cond Setup   ... } DRB-ToAddModList ::= SEQUENCE(SIZE (1..maxDRB)) OF DRB-ToAddMod DRB-ToAddMod ::= SEQUENCE {  eps-BearerIdentity   INTEGER (0..15) OPTIONAL, -- Cond DRB- Setup  drb-Identity   DRB-Identity,   pdcp-Config   PDCP-Config OPTIONAL, --Cond PDCP   rlc-Config   RLC-Config OPTIONAL, -- Cond Setup  logicalChannelIdentity   INTEGER (3..10) OPTIONAL, -- Cond DRB- Setup  logicalChannelConfig   LogicalChannelConfig OPTIONAL, -- Cond Setup  ... } DRB-ToReleaseList ::= SEQUENCE (SIZE (1..maxDRB)) OFDRB-Identity -- ASN1STOP RadioResourceConfigDedicated field descriptionssrb-Identity Value 1 is applicable for SRB1 only. Value 2 is applicablefor SRB2 only. rlc-Config For SRBs a choice is used to indicate whetherthe RLC configuration is signalled explicitly or set to the valuesdefined in the default RLC configuration for SRB1 in 9.2.1.1 or for SRB2in 9.2.1.2. RLC AM is the only applicable RLC mode for SRB1 and SRB2.E-UTRAN does not reconfigure the RLC mode of DRBs, and may reconfigurethe UM RLC SN field size only upon handover within E-UTRA or upon thefirst reconfiguration after RRC connection re-establishment.mac-MainConfig Although the ASN.1 includes a choice that is used toindicate whether the mac-MainConfig is signalled explicitly or set tothe default MAC main configuration as specified in 9.2.2, EUTRAN doesnot apply “defaultValue”. sps-Config The default SPS configuration isspecified in 9.2.3. physicalConfigDedicated The default dedicatedphysical configuration is specified in 9.2.4. logicalChannelConfig ForSRBs a choice is used to indicate whether the logical channelconfiguration is signalled explicitly or set to the default logicalchannel configuration for SRB1 as specified in 9.2.1.1 or for SRB2 asspecified in 9.2.1.2. logicalChannelIdentity The logical channelidentity for both UL and DL. componentCarrierConfig the configuration ofthe component carriers in the case that carrier aggregation is used.Conditional presence Explanation DRB-Setup The field is mandatorypresent if the corresponding DRB is being set up (including bearer setupat handover to E-UTRA); otherwise it is not present. PDCP The field ismandatory present if the corresponding DRB is being setup; the field isoptionally present, need ON, upon handover within E-UTRA and upon thefirst reconfiguration after re- establishment; otherwise it is notpresent. Setup The field is mandatory present if the correspondingSRB/DRB is being setup; otherwise the field is optionally present, needON. HO-Conn The field is mandatory present in case of handover to E-UTRAand to only establish SRB1 in case of RRC connection establishment;otherwise the field is optionally present, need ON. HO-toEUTRA The fieldis mandatory present in case of handover to E-UTRA; In case of RRCconnection establishment and RRC connection re- establishment the fieldis not present; otherwise the field is optionally present, need ON. HO-The field is mandatory present in case of handover to E-UTRA; toEUTRA2otherwise the field is optionally present, need ON.ComponentCarrierConfig The IE ComponentCarrierConfig is used to specifythe configuration of the component carriers in the case that carrieraggregation is used. ComponentCarrierConfig information element-- ASN1START ComponentCarrierConfig ::= SEQUENCE {  componentCarrierToAddModList  SEQUENCE (SIZE (1..MaxCC)) OF SEQUENCE {    physicalComponentCarrierIndex INTEGER {0..7}    logicalComponentCarrierIndex INTEGER {0..7}     componentCarrierSetENUMERATED {candidate, active}     sibType1Info SEQUENCE {      cellIdentity   CellIdentity,       csg-Indication   BOOLEAN,      csg-Identity   BIT STRING (SIZE (27)) OPTIONAL  -- Need OR     },    dl-CarrierFreq ARFCN-ValueEUTRA,     ul-CarrierFreqARFCN-ValueEUTRA,     dl-BandwidthENUMERATED {n6, n15, n25, n50, n75, n100, etc},     ul-BandwidthENUMERATED {n6, n15, n25, n50, n75, n100, etc},    radioResourceConfigCommon RadioResourceConfigCommonSIB,    carrierType ENUMERATED {typeA, typeB},     pdcchMonitoringCarrierBOOLEAN,     systemInformationScheduling SEQUENCE {      schedulingInfoList SchedulingInfoList,       si-WindowLengthENUMERATED {ms1, ms2, ms5, ms10, ms15, ms20, ms40},      systemInfoValueTag INTEGER (0..31),     }  OPTIONAL,    siPaging-Config1  SEQUENCE {       siChangeIndicationPagingCycleENUMERATED {rf32, rf64, rf128, rf256},      siChangeIndicationPagingFrameINTEGER (0..siIndicationPagingCycle),      siChangeIndicationPagingOccassion INTEGER (0..9),     }  OPTIONAL,    siPaging-Config2 SEQUENCE {      siChangeIndicationPagingCyclePeriod INTEGER (1..maxPagingPeriod),      siChangeIndicationPagingFrameINTEGER (1..maxPagingPeriod × PagingCycle on Anchor Carrier)  OPTIONAL,      siChangeIndicationPagingOcassion INTEGER (0..9) OPTIONAL,    }  OPTIONAL,     virtualPCI PhysCellId OPTIONAL,    componentCarrier-C-RNTI C-RNTI OPTIONAL   }  componentCarrierToReleaseList ::=SEQUENCE (SIZE (1..maxCC)) OF SEQUENCE {    logicalComponentCarrierIndex INTEGER (0..7)   } } -- ASN1STOPComponentCarrierConfig field descriptions phyiscalComponentCarrierIndexA carrier index associated with a carrier in the eNB. It is unique amongthe carriers that serve the same geographical area within the eNB.logicalComponentCarrierIndex A logical carrier index that is associatedwith a carrier assigned to the UE. It is unique from a UE's perspective.componentCarrierSet To indicate if the component carrier belongs to theActive CC set and Candidate CC set or just the Candidate CC set.carrierType To indicate if the component carrier is a Type A or Type Bcarrier. pdcchMonitoringCarrier To indicate if the component carrier isa PDCCH monitoring carrier systemInformationScheduling Schedulinginformation for SI on a Type B component carrier.siChangeIndicationPagingCycle Paging cycles for the occurrence of pagingoccasions with SI change indication on the component carriersiChangeIndicationPagingFrame The radio frame within the paging cyclewhere the paging occasion with SI change indication occurs on thecomponent carrier. siChangeIndicationPagingOccasion The subframe withinthe siChangeIndicationPagingFrame where the paging message with SIchange indication is sent on the component carrier.siChangeIndicationPagingCyclePeriod The period of the paging cycles forthe occurrence of paging occasions with SI change indication on thecomponent carrier in multiples of the paging cycle period on the anchorcarrier. 1 means the period is the same as that of the anchor carrier, 2means the period is 2 times that of the anchor carrier and so on and soforth. virtualPCI Virtual PCI of a Type B carrier if a Type B carrier isassigned. componentCarrier-C-RNTI C-RNTI of the UE for the componentcarrier.

In another implementation of step 72 described above and shown in FIG.4, a Type A CC broadcasts some or all of the information types 1) to 9)described above for all other Type A and Type B CCs that serve the samegeographical area. A Type A CC may only broadcast some or all of theinformation types 1) to 9) of other Type A and Type B CCs associatedwith the Type A CC. SI of a CC that is not broadcast can be signaled tothe UE when the base station instructs the UE to enable signal receptionon the CC (e.g., via RRC signaling, MAC control element or PDCCH). Inone implementation, more static and common types of information such asinformation types 1), 2), 4), 7), 8)-physical CC index only, and 9) canbe broadcast while other information can be sent via dedicated signalingto the UE when the base station instructs the UE to enable signalreception on the CC. New SIB types are introduced for a Type A CC tocarry this information. These new SIB types can be transmitted as partof the SI message. The scheduling information of these new SIB types canbe sent in a SIB1 message.

Table 3 shows example RRC signaling to carry CC information in a new SIBtype, i.e., SIB12 shown in this example, according to the abovedescription. SIB1 messages may already signal the scheduling ofcurrently defined SIB types. In order for SIB1 to indicate thescheduling of a new SIB type it may be necessary to redefine a sparevalue of the information element (IE) SIB-Type to represent the newlyintroduced SIB, i.e. SIB12 shown in this example. The changes withrespect to existing RRC signaling in Rel-8 and Rel-9 are underlined.

TABLE 3 SystemInformationBlockType12 The IE SystemInformationBlockType12is transmitted by a cell on a Type A carrier and contains informationabout other component carrier. SystemInformationBlockType12 informationelement -- ASN1START SystemInformationBlockType12 ::= SEQUENCE {  componentCarrierList SEQUENCE (SIZE (1..MaxCC)) OF SEQUENCE {    physicalComponentCarrierIndex INTEGER {0..7}     sibType1InfoSEQUENCE {       cellIdentity   CellIdentity,       csg-Indication  BOOLEAN,       csg-Identity   BIT STRING (SIZE (27)) OPTIONAL  -- NeedOR     },     dl-CarrierFreq ARFCN-ValueEUTRA,     ul-CarrierFreqARFCN-ValueEUTRA,     dl-BandwidthENUMERATED {n6, n15, n25, n50, n75, n100, etc},     ul-BandwidthENUMERATED {n6, n15, n25, n50, n75, n100, etc},    radioResourceConfigCommon RadioResourceConfigCommonSIB,    carrierType ENUMERATED {typeA, typeB},     pdcchMonitoringCarrierBOOLEAN,     systemInformationScheduling SEQUENCE {      schedulingInfoList SchedulingInfoList,       si-WindowLengthENUMERATED {ms1, ms2, ms5, ms10, ms15, ms20, ms40},      systemInfoValueTag INTEGER (0..31),     }  OPTIONAL,    siPaging-Config SEQUENCE {       siChangeIndicationPagingCycleENUMERATED {rf32, rf64, rf128, rf256},      siChangeIndicationPagingFrameINTEGER (0..siIndicationPagingCycle),      siChangeIndicationPagingOccassion INTEGER (0..9),     }  OPTIONAL,    virtualPCI PhysCellId OPTIONAL,       } } -- ASN1STOP

The base station may instruct a UE to measure the RSRP/RSRQ of a CC thatmay be in the UE's Active CC Set or a CC that is not in the UE's ActiveCC Set, but is in the UE's Candidate CC Set. The base station may alsoinstruct a UE to measure the RSRP/RSRQ of a CC that is not in the UE'sCandidate CC Set. One of the reasons that the base station may instructa UE to measure and report RSRP/RSRQ on a CC that is not in the UE'sActive CC set is to measure the received signal and interference levelof the CC at the UE to assist the base station to decide whether toassign the CC to the UE's Active CC set.

Activation of a Carrier within the Candidate Carrier Set

In the present system, the base station may signal the UE to activate orenable signal reception on a CC within the Candidate CC Set for the UE.The signaling can be sent on the anchor CC or one of the CCs within theUE's Active Carrier Set. If the SI (e.g., SIB2 information and/or otherinformation) for the CC has not changed from what has previously beenprovided to the UE, the base station may activate the CC using a MACcontrol element. If the signaling is sent using a MAC control element,it can be sent on the anchor CC or one of the CCs within the ActiveCarrier Set. If the signaling is sent on the PDCCH, the signaling may besent on one of PDCCH monitoring carriers within the Active Carrier Set.The logical carrier index of the CC, and possibly an Action Time, areincluded in the MAC control element or PDCCH. The Action Time defines aradio frame and subframe where the UE should enable signal reception onthe CC indexed by the logical carrier index. In the case of DRXoperation, if DRX parameters are configured for a CC within theCandidate CC Set, the UE may enable signal reception on the CC duringthe Active time of the DRX cycle.

If, however, the SI information has changed from what has previouslybeen provided to the UE, the base station may use RRC signaling toactivate the CC. The RRC signaling may include the physical or logicalcarrier index of the CC, the Action Time when the UE should enablesignal reception on the CC, the updated or delta SIB2 information of theCC with respect to those of the anchor CC, and other updated informationof the CC. Alternatively, MAC control elements or the PDDCH can be usedto activate a CC. In that case, the MAC control element or the PDCCHincludes a field to indicate to the UE whether there is updated SIB2information on the CC. If there is updated SIB2 information, if the CCis a Type A carrier, the UE decodes the updated SIB2 information on theCC itself. The UE may decode the SIB2 information on the CC prior to theAction Time. For example, the UE may enable signal reception on the CCto decode SIB1 to read the scheduling information of SIB2 andsubsequently decode SIB2 at the appropriate subframes. In anotherimplementation, the UE only decodes the SIB2 information on the CC afterthe Action Time. In that case, there may be a delay associated with whenthe base station can schedule PDSCH and PUSCH transmissions for the UEon the CC. The UE may inform the base station via signaling such as RRCsignaling after it has successfully decoded the SIB2 information.

If the CC is a Type B CC, the CC may or may not transmit SIB2information as described above. If the Type B CC transmits SIB2information, a MAC control element or PDCCH may be used to activate theCC as described above. If, however, the Type B CC does not transmit SIB2information, the base station may use RRC signaling to activate the CC,with the RRC signaling including the updated or delta SIB2 informationof the CC.

In the case of DRX operation, while not in Active Time, the UE mayacquire the updated SIB2 information prior to the start of the nextActive Time. For example, the UE may enable signal reception on the CCprior to the next Active Time to decode SIB1 messages to read thesystemInfoValueTag and scheduling information of the SIB2 andsubsequently decode the SIB2 at the appropriate subframes.Alternatively, the UE may monitor the paging occasions on the anchor CCor the CC itself to determine whether there is an update to the SI atthe next modification period boundary.

Switching of Anchor Carrier

The base station may be configured to signal a UE to switch the UE'sanchor CC to an alternate Type A CC. In the present system, if thetarget anchor CC is a CC within the UE's Active CC Set, the base stationtransmits an RRC signaling message or MAC control element to the UE thatincludes the logical carrier index of the target anchor CC and/orpossibly the Action Time of when the switch should occur. RRC signalingand MAC control elements may be configured to include an indication thatthe CC is the anchor CC of the UE at the specified action time. In oneimplementation, the RRC signaling to indicate the switch to a targetanchor carrier may include the additional SI required for properoperation when the UE switches to the new anchor carrier. The additionalSI may not be part of the SI that the UE has previously acquired orreceived from the base station because only a subset of the full SI maybe required when a carrier is a non-anchor carrier whereas a full set ofSI may be required when a carrier becomes the anchor carrier.

Table 4 shows example RRC signaling to activate or de-activate acomponent CC and designate a component CC as the anchor CC as describedabove. The changes with respect to the RadioResourceConfigDedicated IEin Rel-8 and Rel-9 are underlined.

TABLE 4 RadioResourceConfigDedicated The IE RadioResourceConfigDedicatedis used to setup/modify/release RBs, to modify the MAC mainconfiguration, to modify the SPS configuration and to modify dedicatedphysical configuration. RadioResourceConfigDedicated information element-- ASN1START RadioResourceConfigDedicated ::= SEQUENCE {  srb-ToAddModList SRB-ToAddModList OPTIONAL, -- Cond HO-Conn  drb-ToAddModList DRB-ToAddModList OPTIONAL, -- Cond HO-toEUTRA  drb-ToReleaseList DRB-ToReleaseList OPTIONAL, -- Need ON  mac-MainConfig CHOICE {       explicitValue   MAC-MainConfig,      defaultValue   NULL   }    OPTIONAL, -- Cond HO-toEUTRA2  sps-Config SPS-Config OPTIONAL, -- Need ON   physicalConfigDedicatedPhysicalConfigDedicated OPTIONAL, -- Need ON   ...  componentCarrierActivationInfo ComponentCarrierActivationInfo OPTIONAL} SRB-ToAddModList ::= SEQUENCE (SIZE (1..2)) OF SRB-ToAddModSRB-ToAddMod ::= SEQUENCE {   srb-Identity INTEGER (1..2),   rlc-ConfigCHOICE {     explicitValue   RLC-Config,     defaultValue   NULL  }    OPTIONAL, -- Cond Setup   logicalChannelConfig CHOICE {    explicitValue   LogicalChannelConfig,     defaultValue   NULL  }    OPTIONAL, -- Cond Setup   ... } DRB-ToAddModList ::= SEQUENCE(SIZE (1..maxDRB)) OF DRB-ToAddMod DRB-ToAddMod ::= SEQUENCE {  eps-BearerIdentity INTEGER (0..15) OPTIONAL, -- Cond DRB- Setup  drb-Identity DRB-Identity,   pdcp-Config PDCP-Config OPTIONAL, -- CondPDCP   rlc-Config RLC-Config OPTIONAL, -- Cond Setup  logicalChannelIdentity INTEGER (3..10) OPTIONAL, -- Cond DRB- Setup  logicalChannelConfig LogicalChannelConfig OPTIONAL, -- Cond Setup  ... } DRB-ToReleaseList ::= SEQUENCE (SIZE (1..maxDRB)) OFDRB-Identity ComponentCarrierActivationInfo ::=SEQUENCE (SIZE (1..macXX)) OF SEQUENCE{     logicalComponentCarrierIndex        INTEGER {0..7}     componentCarrierSet    ENUMERATED {inactive, active} OPTIONAL,     actionTime SEQUENCE{      systemFrameNumber BIT STRING (SIZE (10)),       subFrameNumberINTEGER (0..9)     }  OPTIONAL,     anchorCarrierIndication BOOLEAN    radioResourceConfigCommon RadioResourceConfigCommonSIB OPTIONAL } --ASN1STOP RadioResourceConfigDedicated field descriptionscomponentCarrierSet If the field is set to active then the componentcarrier is active (i.e. it is member of the Active Component CarrierSet). If the field is set to inactive then the component carrier isinactive (i.e. it is a member of the Candidate Component Carrier Set).systemFrameNumber The 10-bit SFN of the radio frame on which thecomponent carrier is activated. subFrameNumber The subframe within theradio frame on which the component carrier is activated.anchorCarrierIndication Set to ‘True’ if the component carrier is theanchor carrier at the actionTime. Set to ‘False’ otherwise.

Table 5 shows an example of signaling via a MAC Control Element (MAC CE)to activate or de-activate a CC for a particular UE. In the exampleshown in Table 5, up to 8 CCs can be activated/de-activated using thesame MAC CE. The changes with respect to Rel-8 and Rel-9 are underlined.FIG. 10 is an illustration of an example Component Carrier Control MACcontrol element.

TABLE 5 6.1.3.x Component Carrier Control MAC Control Element TheComponent Carrier Control MAC control element (see FIG. 10) isidentified by MAC PDU subheader with LCID as specified in table 6.2.1-2.It has a fixed size and consists of 8 fields A0 to A7 as well as twoadditional fields defined as follows (FIG. 6.1.3.x-1): An: If the fieldis set to 1 then the component carrier with logical or physicalcomponent carrier index n is active (i.e. it is a member of the ActiveComponent Carrier Set). If the field is set to 0 then the componentcarrier with logical/physical component carrier index n is inactive(i.e. it is a member of the Candidate Component Carrier Set). LSB_SFN:Four LSB of the SFN for next radio frame on which the UE should enablesignal reception on the component carriers indicated in A0 to A7.SubframeIndex: The index of the subframe within the radio frame on whichthe UE should enable signal reception on the component carriersindicated in A0 to A7. 6.2.1 MAC header for DL-SCH and UL-SCH The MACheader is of variable size and consists of the following fields: LCID:The Logical Channel ID field identifies the logical channel instance ofthe corresponding MAC SDU or the type of the corresponding MAC controlelement or padding as described in tables 6.2.1-1 and 6.2.1-2 for the DLand UL-SCH respectively. There is one LCID field for each MAC SDU, MACcontrol element or padding included in the MAC PDU. In addition to that,one or two additional LCID fields are included in the MAC PDU, whensingle-byte or two-byte padding is required but cannot be achieved bypadding at the end of the MAC PDU. The LCID field size is 5 bits; L: TheLength field indicates the length of the corresponding MAC SDU in bytes.There is one L field per MAC PDU subheader except for the last subheaderand subheaders corresponding to fixed-sized MAC control elements. Thesize of the L field is indicated by the F field; F: The Format fieldindicates the size of the Length field as indicated in table 6.2.1-3.There is one F field per MAC PDU subheader except for the last subheaderand subheaders corresponding to fixed-sized MAC control elements. Thesize of the F field is 1 bit. If the size of the MAC SDU is less than128 bytes, the UE shall set the value of the F field to 0, otherwise theUE shall set it to 1; E: The Extension field is a flag indicating ifmore fields are present in the MAC header or not. The E field is set to“1” to indicate another set of at least R/R/E/LCID fields. The E fieldis set to “0” to indicate that either a MAC SDU, a MAC control elementor padding starts at the next byte; R: Reserved bit, set to “0”. The MACheader and subheaders are octet aligned. Index LCID values Values ofLCID for DL-SCH 00000 CCCH 00001-01010 Identity of the logical channel01011-11010 Reserved 11011 Component Carrier Control 11100 UE ContentionResolution Identity 11101 Timing Advance Command 11110 DRX Command 11111Padding Values of LCID for UL-SCH 00000 CCCH 00001-01010 Identity of thelogical channel 01011-11001 Reserved 11010 Power Headroom Report 11011C-RNTI 11100 Truncated BSR 11101 Short BSR 11110 Long BSR 11111 PaddingValues of F field: Index Size of Length field (in bits) 0  7 1 15

Table 6 shows another example of MAC CE to activate, de-activate orde-allocate a CC and designate it as the target anchor CC in the case ofactivation. The changes with respect to Rel-8 and Rel-9 are underlined.FIG. 11 is an illustration of the example Component Carrier Control MACcontrol element.

TABLE 6 6.1.3.x Component Carrier Control MAC Control Element TheComponent Carrier Control MAC control element (see FIG. 11) isidentified by MAC PDU subheader with LCID as specified in table 6.2.1-2.It has a fixed size and consists of fields defined as follows (FIG.6.1.3.x-1): CC_index: logical or physical component carrier index. A/D:Set to ‘00’ to indicate the component carrier is de-allocated from theUE, i.e., the component carrier is no longer in the UE's CandidateComponent Carrier Set or Active Component Carrier set; set to ‘01’ toindicate the component carrier is de-activated, i.e. the UE shalldisable signal reception on the carrier but the carrier remains in theUE's Candidate Component Carrier Set; set to ‘10’ to indicate thecomponent carrier is activated, i.e. the UE shall enable signalreception on the carrier and the carrier is in UE's Active ComponentCarrier Set; ‘11’ is a reserved value. AC: If A/D is set to ‘10’, thisbit is set to ‘1’ to indicate the component carrier is the target anchorcarrier. Set to ‘0’ otherwise. LSB_SFN: Four LSB of the SFN for nextradio frame on which the UE should enable signal reception on thecomponent carriers indicated in A0 to A7. SubframeIndex: The index ofthe subframe within the radio frame on which the UE should take theaction indicated by A/D on the component carrier indicated by CC_index.R: Reserved bits set to 0.

If the target anchor CC is within the Active CC Set of the UE, the basestation may use the PDCCH to instruct the UE to switch its anchor CC tothe target anchor CC. The PDCCH can be sent on the current anchor CC orthe target anchor CC for the UE if the target anchor CC is a PDCCHmonitoring carrier. Alternatively, the PDCCH can be sent using any ofthe PDCCH monitoring CCs within the Active CC Set.

The security keys for the UE on the target anchor CC may be derivedbased on an existing CC or cell's K_(eNB) and the target anchor CC/cellPCI and carrier frequency of the target anchor CC, as described above.In that case, the RLC sublayer and PDCP sublayer re-establishment may beperformed after the UE switches to the new anchor CC at the Action time.Random access procedures on the associated uplink CC, which are normallyperformed for regular inter-cell handover, may be omitted. Random accessprocedures may be required, however, if the UL CC associated with thenew anchor CC is on a different band than currently assigned UL CCs. Assuch, there may be some service interruption due to RLC and PDCPre-establishment. Alternatively, the security keys for the UE do notchange when a UE switches from one anchor CC to another anchor CC. Inthat case, the RLC sublayer and PDCP sublayer re-establishment may beomitted after the UE switches to the new anchor CC. Also, random accessprocedures on the associated uplink CC, which are normally performed forregular inter-cell handover, may be omitted.

In one implementation, the security keys for the UE are derived based onexisting CC/cell's K_(eNB) and the target anchor CC/cell PCI and carrierfrequency of the target anchor CC, as described above. The RLC sublayerand PDCP sublayer re-establishment may be omitted after the UE switchesto the new anchor CC. The base station may indicate the starting PDCPsequence number (SN) for each configured radio bearer where the newsecurity keys for the target anchor CC will take effect to the UE viasignaling such as RRC signaling or a MAC control element. In that case,after the UE re-assembles the RLC SDU or PDCP PDU, if the PDCP sequencenumber is less than the starting PDCP sequence number indicated by thebase station, the PDCP PDU will correspond to the old security keys usedfor the previous anchor CC. If the PDCP sequence number is equal orlarger than the starting PDCP sequence number indicated by the basestation, the PDCP PDU will correspond to the new security keys for thenew anchor CC. Alternatively, the new security keys for the targetanchor CC will apply on the first new PDCP packet for each configuredradio bearer after the UE switches to the target anchor CC. PDCP packetsgenerated on the source anchor CC and still undergoing RLC transmissionsor retransmissions may continue to use the security keys correspondingto the source anchor CC. In that case, after the UE re-assembles the RLCSDU, if any of the RLC segments or PDUs of that SDU are received priorto the Action Time, that RLC SDU or PDCP PDU will correspond to the oldsecurity keys. Otherwise, the RLC SDU or PDCP PDU will correspond to thenew security keys. Random access procedures on the associated uplink CC,which are normally performed for regular inter-cell handover, may beomitted.

PDSCH/PUSCH/PDCCH Scrambling

In existing network implementations, the PDSCH/PUSCH, and PDCCH of anassigned carrier to the UE may be scrambled using a combination of theRNTI and cell ID for the carrier. Existing scrambling techniques aredescribed in section 6.3.1 (PDSCH), 5.3.1 (PUSCH), and 6.8.2 (PDCCH) of3GPP TS 36.211, v 8.7.0, 3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network; Evolved Universal TerrestrialRadio Access (E-UTRA); Physical Channels and Modulation (Release 8),June 2009. In multi-carrier network implementations, however, in whichone or more CCs (e.g., Type B CCs) may not be defined as cells making itdifficult to identify appropriate RNTI and cell ID values, it may bedifficult to implement scrambling of one or more channels of aparticular CC.

In the present system, to implement channel scrambling in Type A CCs,different C-RNTI values may be allocated to each Type A CC assigned tothe UE as a candidate CC by the base station. In that case, the basestation scrambles the control and traffic channels using the cell ID andC-RNTI values that correspond to the CC containing the control ortraffic channel. This implementation allows for the assignment ofindependent C-RNTI values to a UE for each of the type A CCs accessibleto the UE. In the case of a Type A CC that is not a PDCCH-monitoringcarrier for the UE, the C-RNTI value may be used for the purpose ofPDSCH/PUSCH scrambling.

Alternatively, when implementing scrambling on Type A CCs, the basestation may assign a single RNTI value to a UE for all CCs in the UE'sActive CC Set or Candidate CC Set. The single RNTI value may be a valuethat correspond to the anchor CC of the UE. In some cases, the basestation may reserve the RNTI value for all CCs in the Candidate CC setto ensure that the RNTI value is available when the base station needsto activate these CCs. The scrambling on all the CCs may then be basedon the cell ID of the Type A CC and the assigned RNTI value.

When implementing scrambling on Type B CCs, each Type B CC may beassigned a virtual RNTI, virtual cell ID or PCI values for both DL andUL channels by the base station. Because Type B CCs are not classifiedas cells, the RNTI, cell ID and PCI values are virtual. The virtual cellID management may be deployment specific and can be managed as part ofcell planning strategy similar to cell ID management. After the virtualcell ID is assigned to a Type B CC, the base station may manage its RNTIvalues for the virtual cell independently. The virtual cell ID can betransmitted to the UE using synchronization signals including the PSSand SSS. When PSS and SSS are not transmitted on a Type B CC, the basestation can signal the virtual cell ID to the UE via RRC signaling. Thescrambling on each Type B CC is then based on assigned virtual RNTI andvirtual cell ID. Alternatively, a single RNTI may be assigned to the UEfor scrambling on all active CCs. In this case, the scrambling on eachType B CC is then based on the virtual cell ID of the CC and theassigned RNTI value. In this implementation, the base station may beconfigured to maintain a registry identifying which cell ID to use forscrambling for the same type B CC that varies per transmission timeinterval (TTI).

Alternatively, for each Type B CC, the scrambling for the PDSCH/PUSCHand PDCCH (if present) may correspond to (e.g., be equal to, or be apredictable modification of) that of the anchor CC (or anotherdesignated Type A CC). This option may also be applied to othernon-anchor Type A CCs. In this implementation, all CCs for a given UEmay use the same scrambling, as determined by the PCI and RNTI of theanchor CC or a particular assigned RNTI for all CCs.

In some cases, the PDCCH of one carrier may be configured to makePDSCH/PUSCH resource allocations on multiple CCs, including the CC viawhich the PDCCH was originally transmitted. FIG. 5 illustrates a controlchannel implementation where a single PDCCH 80 may allocate resources onone or more CCs. As shown, the PDCCH 82 on CC f1 only allocatesresources on CC f1. However, the PDCCH 80 on CC f2 allocates resourceson both CCs f2 and f3. In this example, CC f3 does not include a PDCCHas its resources may be allocated by PDCCH 80 of CC f2.

Using the control channel configuration shown in FIG. 5, scrambling ofPDCCH 80 that allocates PDSCH/PUSCH resources on CC f3 may beimplemented using the C-RNTI/cell ID corresponding to the PDCCH 80 on CCf2. The scrambling of PDSCH/PUSCH on CC f3 may be implemented using theC-RNTI/cell ID corresponding to the PDSCH/PUSCH on CC f2. In thisexample, CC f2 shown on FIG. 5 is the CC transmitting the PDCCH and CCf3 is the CC transmitting the PDSCH/PUSCH.

Alternatively, when allocating PDSCH/PUSCH resources on CC f3, PDCCH 80scrambling on CC f2 may use the C-RNTI/cell ID corresponding to thePDSCH/PUSCH CC f3. Conversely, when allocating PDSCH/PUSCH resources onCC f2, PDCCH 80 scrambling on CC f2 may use the C-RNTI/cell IDcorresponding to the PDSCH/PUSCH CC f2. This configuration allows thebase station to indicate the PDSCH/PUSCH CC implicitly via the PDCCH CCscrambling. In this implementation, the UE may be required to performblind decoding on each PDCCH candidate using each potential C-RNTI/cellID (e.g., by using the C-RNTI/cell ID of each of CCs f2 and f3 toattempt to decode PDCCH 80 on CC f2). If the CRC check is successful,the PDCCH corresponds to the CC having the C-RNTI/cell ID which was usedto successfully blind decode the PDCCH candidate. This method foridentifying the CC upon which the PDCCH allocates resources may beadvantageous, because there are zero bits in the PDCCH used to indicatethe CC to which PDSCH/PUSCH resources are assigned, saving overhead.

Linkage of DL and UL Carriers

In LTE Rel-8/9 each DL carrier is linked to a single UL carrier based onSI and the UE may always deal with one pair of DL/UL carriers. In LTE-Ahowever, a UE configured with carrier aggregation (CA) may need tointeract with base station's on multiple and sometimes unequal numbersof DL and UL carriers. Therefore, proper linkage between the configuredDL and UL CCs need to be defined for UL grant sent on the PDCCH. Thelinkage of UL grant is required for two reasons. First, when crosscarrier allocation is not configured, the PDCCH with UL grant sent on aDL carrier should point to the linked UL carrier. The linkage can bebased on that indicated in the SI of the DL carrier. Second, when crosscarrier scheduling is configured, the UL grant sent on the PDCCH of a DLcarrier includes a CIF to point to the corresponding UL carrier to whichthe UL grant applies. The same DL carrier may transmit PDCCHs (ULgrants) with different CIF values to point to different linked ULcarriers.

In one embodiment, the UL carrier(s) associated with a DL carrier wherecross carrier scheduling can be applied are signaled by the base stationto the UE through RRC signaling. A UL carrier may be associated withmultiple DL carriers. In one implementation, in the RRC signaling thatassigns a DL carrier and/or UL carrier to a UE, the signaling messagemay include information of the SI-based pairing of the DL/UL carriers aswell as the linkage between assigned DL carrier(s) and the correspondingassigned UL carrier(s) where cross carrier scheduling is performed. Asan illustration, DL carrier #1 and UL carrier #1 may be assigned to a UEand are paired DL-UL carriers based on SI. A UL grant without CIF senton the PDCCH of DL carrier #1 assigns PUSCH resource on UL carrier #1 tothe UE. In addition, the UE may be assigned DL carrier #2. In the RRCsignaling message that indicates the assignment of DL carrier #2 to theUE, the signaling message also indicates that DL carrier #2 can performcross-carrier scheduling on UL carrier #1. A UL grant sent on the PDCCHof DL carrier #2, with CIF set to the carrier index of UL carrier #1,assigns PUSCH resource on UL carrier #1. Additional DL carriers may alsobe assigned to the UE and can perform cross-carrier scheduling on ULcarrier #1.

In one implementation, a UL carrier may only be scheduled by one activeDL carrier at a time although multiple DL carriers may be configured tobe able to schedule a UL carrier. In the example shown above, the PUSCHresource on UL carrier #1 can only be scheduled by either DL carrier #1(i.e. without cross-carrier scheduling) or DL carrier #2 (i.e. withcross-carrier scheduling using CIF), but not both at the same time. Inthat case, the following are possible solutions to determine at aparticular time which DL carrier is responsible for scheduling an ULcarrier: First, when the DL carrier linked by SI is active, thecorresponding UL carrier may only be scheduled by that DL carrier, i.e.without using cross-carrier scheduling. Second, when the DL carrierlinked by SI is not active, the UL carrier is scheduled by one of theactive DL carriers linked by cross-carrier scheduling. If multiple DLcarriers linked to the UL carrier through cross-carrier scheduling areactive, some predefined rules may be used to determine which DL carriershould perform the cross carrier scheduling. In one implementation, theDL carrier with the lowest (or highest) carrier index should be used.Third, when none of the DL carriers linked to a UL carrier (eitherthrough SI or through cross-carrier scheduling) is active, the DL anchorcarrier may be used to perform cross-carrier scheduling on the ULcarrier. Alternatively, when none of the DL carrier(s) linked to a ULcarrier (either through SI or through cross-carrier scheduling) isactive, the UL carrier may not be scheduled by the base station. The UEmay stop certain control channel and/or control informationtransmissions, such as Sound Reference Signal (SRS) and/or powerheadroom report, of the UL carrier.

In one implementation, multiple DL carriers can be linked to one ULcarrier, with the UL carrier being scheduled by only one of the activeDL carriers which is selected based upon some predefined or configuredpriority. In RRC signaling that assigns a DL and/or UL carrier to a UE,the signaling message may include linkage information of the multiple DLcarriers for a UL carrier and the associated priority of each DLcarrier. For example, DL carrier #1 and DL carrier #2 may be linked toUL carrier #1 and DL carrier #1 has higher priority. In this case, if DLcarrier #1 is active, the UL carrier is scheduled only by DL carrier #1.If, however, DL carrier #1 is deactivated and DL carrier #2 is active,the UL carrier may be scheduled by DL carrier #2. Alternatively, thepriority can be implicitly determined. For example, DL carriers linkedby SI can have the highest priority or DL anchor carrier can have thelowest priority or DL PCC can have the highest priority, or the priorityorder of the DL carriers follows increasing or decreasing order of thecarrier index etc. If multiple DL carriers have the same priority, otherpredefined rules, such as those based upon whether the active DL carrierhas the lowest carrier index, are used to determine which DL carrier isused to schedule the UL carrier.

The above implementations can also be applied to cross-carrierscheduling of DL carriers. The PDCCH sent on a DL carrier can indicatePDSCH resource assignment on another DL carrier, by including the CIF inthe DCI. In one implementation, when a DL carrier is assigned to the UEvia RRC signaling, the other linked DL carrier(s) that can performcross-carrier scheduling on this DL carrier are also indicated in theRRC signaling. A DL carrier may only be scheduled by one DL carrier at atime. If a DL carrier is configured to be cross-carrier scheduled byanother DL carrier, the PDSCH resource of this carrier may only beassigned by another linked DL carrier. When there are multiple linked DLcarriers active, some predefined rules can be used to determine whichlinked DL carrier is used to perform cross-carrier scheduling on this DLcarrier. For example, the DL carrier with the lowest (or highest)carrier index could be used. When none of the linked DL carriers areactive, the DL anchor carrier is used to perform cross-carrierscheduling on this DL carrier. Alternatively, when none of the linked DLcarriers are active, the DL carrier is considered deactivated and the UEmay stop signal reception on the DL carrier.

In one implementation, the carrier activation/deactivation command forDL carrier(s) (e.g. using a MAC control element) may include anindication (e.g. a single bit) indicating whether the UE should performimplicit remapping of the DL carrier that is responsible for schedulingof a UL carrier based on the above-defined rules. For example, if thebit is set to ‘1’, the UE may perform implicit remapping of the DLcarrier that is responsible for scheduling of an UL carrier. If,however, the bit is set to ‘0’, the UE may not perform implicitremapping. If the bit is set ‘0’ for the case of DL carrier(s)deactivation, the UL carrier(s) linked to the deactivated DL carrier(s)may not be scheduled by the base station. The UE may stop certaincontrol channel and/or control information transmission, such as SoundReference Signal (SRS) and/or power headroom reports, of those ULcarrier(s). In one case, there may be no implicit remapping defined forthe linkage between a UL carrier and the DL carriers that can schedulethis UL carrier. If all the DL carrier(s) that can schedule a UL carrierare deactivated, the UL carrier may not be scheduled by the basestation. The UE may stop certain control channel and/or controlinformation transmission, such as Sound Reference Signal (SRS) and/orpower headroom report, of the UL carrier.

In another implementation, the carrier activation/deactivation commandfor DL carrier(s) (e.g. using MAC control element) may include anindication (e.g. 1 bit) indicating whether the UE should performimplicit remapping between an active DL PDCCH monitoring carrier and theDL carrier(s) that it can schedule, based on the above predefined rules.For example, if the bit is set to ‘1’, the UE may perform implicitremapping. If, however, the bit is set to ‘0’, the UE may not performimplicit remapping. If the bit is set ‘0’ for the case of DL carrier(s)deactivation or if implicit remapping is not supported, the DLcarrier(s) linked to the deactivated DL carrier(s) may not be scheduledby the base station. This may lead to implicit deactivation of thoselinked DL carrier(s) and the UE may stop signal reception on thoselinked DL carrier(s). In one implementation, there may be no implicitremapping defined between DL carrier(s). If all the DL PDCCH-monitoringcarrier(s) that can schedule a DL carrier are deactivated, the DLcarrier may not be scheduled by the base station. This may lead toimplicit deactivation of the DL carrier and the UE may stop signalreception on the DL carrier.

In yet another implementation, a DL or UL carrier may be configured(e.g. through RRC signaling) to be linked to multiple DL carriers thatcan schedule the DL/UL carrier. Each of the configured linkage isassociated with a linkage index included in the RRC signaling. When thebase station (e.g., eNB) sends a DL carrier activation/deactivationcommand to the UE, e.g. through MAC control element, the linkage indexto be used after the activation/deactivation is also included in the MACcontrol element. The UE will apply the linkage associated with thelinkage index after receiving the MAC control element.

In yet another implementation, when the base station (e.g., eNB) sends acarrier deactivation command to the UE (e.g. through MAC controlelement), the eNB may include an indication whether the UE should alsodeactivate the UL carrier(s) linked to the deactivated DL carrier, forexample, stopping certain UL control channel/information transmissionsuch as SRS and/or PHR, of the UL carrier(s).

Random Access Procedures for UL Carriers

In LTE Rel-8/9, because there may be only one DL-UL carrier pair, thetransmission of random access preamble from the UE, the transmission ofrandom access response from the eNB, the corresponding adjustment of ULtransmission time and transmit power at the UE are all confined withinthe DL-UL carrier pair. In LTE-A, there may be multiple DL and ULcarriers assigned to the UE. The multiple DL and UL carriers may be indifferent bands which may be far apart. Some carriers may be deployed atdifferent locations than the base station (e.g. at repeaters, RemoteRadio Head (RRH)), or some carriers may have different antenna patternsthan other carriers. In that case, the random access procedure can beenhanced to take into consideration different path loss and propagationdelay experienced at different carriers.

In one implementation of the present system, carriers deployed within abase station geographic area (i.e. including the carriers deployed atrepeaters and RRH as part of the overall base station transceiver chain)are grouped according the expected path loss (PL) and propagation delay(PD). Carriers that have similar PL and PD are grouped into the samegroup. The DL carrier and the paired UL carrier indicated in the SI ofthe DL carrier may have the same or similar PL and PD. When a DL or ULcarrier is assigned to a UE, the associated carrier group may also beindicated to the UE in the carrier assignment RRC signaling. A UE may beassigned DL/UL carriers belonging to different carrier groups. Inanother implementation, the DL carrier and paired UL carrier indicatedin the SI of the DL carrier may have different PL and/or PD. This may befor the case where there are multiple DL carriers deployed on multiplebands while the UL carriers are deployed on only a subset of the bandswhere DL carriers are deployed. In this case, the DL carrier and the ULcarrier linked by SI may belong to different bands and thereforedifferent carrier groups. In one implementation, when a UE is assignedan UL carrier in a particular carrier group, the UE may also be assigneda DL carrier in the same carrier group.

In the present implementation, the following random access procedure andtiming adjustment strategy may be implemented between the UE and thebase station:

First, each carrier group maintains an associated set of RA relatedparameters and values, i.e. similar to the set of RA related parametersin LTE Rel-8/9 such as timers, counter, transmit power relatedparameters etc. Different carrier groups may maintain different sets ofRA related parameters and values.

Second, there may be only one random access (RA) procedure on-going at atime within a carrier group. When there are multiple carrier groupsassigned to the UE, there can be multiple corresponding random accessprocedures on-going at a time.

Third, for each carrier group, one designated UL carrier may be used totransmit the Random Access Preamble on the Physical Random AccessChannel (PRACH). In one implementation, the designated UL carrier may bea UL anchor carrier if the UL anchor carrier belongs to the carriergroup. Alternatively, any UL carrier within the carrier group can beused to transmit the RA preamble. Alternatively, only UL carriers wherethe paired DL carriers (as indicated in the SI) are active transmit theRA preamble. The DL carrier used by the base station to transmit the RAresponse is the corresponding DL carrier that indicates the UL RAresource used by the UE to transmit the RA preamble.

Fourth, the transmit power setting of the RA preamble sent on theselected PRACH of a UL carrier may be based on the DL PL estimated fromany of the DL carriers or any of the active DL carriers in the samecarrier group. Alternatively, the transmit power setting of the RApreamble sent on a UL carrier is based on the DL PL estimated from adesignated DL carrier (e.g. the DL anchor carrier if the DL anchorcarrier is within the carrier group) within the carrier group. Inanother alternate solution, the transmit power setting of the RApreamble sent on a UL carrier is based on the DL PL estimated from thepaired DL carrier indicated in the SI. In another alternateimplementation where the RA preamble transmission is instructed by thebase station (e.g., eNB) (e.g. using PDCCH order sent to the UE), the UEshall use the DL carrier that transmits the PDCCH order as reference forDL PL estimation.

Fifth, any of the DL carriers or any of the active DL carriers within acarrier group may be used as reference for DL PL estimation of UL powercontrol of any of the UL carriers in the same carrier group.Alternatively, one designated DL carrier (e.g. the DL anchor carrier ifthe DL anchor carrier is within the carrier group) within the carriergroup is used as the reference for DL PL estimation. Alternatively, theUL power control of a UL carrier is based on DL PL estimation on thepaired DL carrier indicated in the SI. When triggered by changes inestimated PL larger than a configured threshold or by timer expiry,power Headroom Report (PHR) is sent by the UE to the base station (e.g.,eNB) to report the power headroom available for a particular UL carrieror for all the UL carriers in the same carrier group. A single PHR on aUL carrier may be used to represent the same power headroom value of allthe other UL carriers in the same carrier group. The eNB may configurewhether PHR should be sent for a particular UL carrier. In oneimplementation, PHR should always be required for the UL anchor carrierwhile the eNB may configure whether PHR is needed on a particularconfigured UL non-anchor carrier.

Sixth, the base station may send a PDCCH order on any of the active DLcarriers within a carrier group to instruct the UE to perform RApreamble transmission on a particular UL carrier within the same carriergroup. A CIF is included in the PDCCH order to indicate which UL carrierthe UE should transmit the RA preamble. Alternatively, the base stationmay send a PDCCH order on any of the active DL carriers within a carriergroup but the UL carrier on which the UE should send the RA preamble isthe UL carrier linked to the DL carrier (as indicated in the SI) onwhich the PDCCH order is sent. In another implementation, the basestation may only send the PDCCH order on a designated active DL carrierwithin the carrier group (e.g. the DL anchor carrier if the DL anchorcarrier is within the carrier group). The PDCCH order may include CIF toindicate a particular UL carrier within the carrier group where the ULshould transmit the RA preamble. Alternatively, the PDCCH order does notinclude a CIF and the UE transmits the RA preamble on a designated ULcarrier (e.g. the UL anchor carrier, i.e. the carrier linked to the DLanchor carrier as indicated in the SI if the UL anchor carrier is withinthe carrier group). Alternatively, the base station may send a PDCCHorder on any active DL carriers to instruct the UE to transmit the RApreamble on any UL carrier (i.e. not limiting to the UL carrier withinthe same carrier group as the DL carrier on which the PDCCH order istransmitted) indicated by the CIF.

Seventh, one UL transmission timing reference may be maintained for allUL carriers within the same carrier group. The UL transmission timingreference may be based upon the DL reception timing of any of the DLcarriers or any active DL carriers within the same group. Alternatively,the UL transmission timing reference may be based on the DL receptiontiming of one designated DL carrier (e.g. the DL anchor carrier if theDL anchor carrier is within the carrier group) within the same group.

Eighth, the Timing Advance (TA) Command MAC control element (CE) sentfrom the base station to the UE may be designated to a particularcarrier group. A carrier group index may be included in the TA CommandMAC CE to indicate the carrier group to which the TA should be applied.When a TA Command MAC CE for a particular carrier group is received atthe UE, the UE may adjust the UL transmission timing reference for allthe UL carriers belong to the carrier group. In another implementation,a carrier group index may not be included in the TA Command MAC CE. Whena TA Command MAC CE is received by the UE on a particular DL carrier,the UE may adjust the UL transmission timing reference for all the ULcarriers belong to the same carrier group as the DL carrier. In yetanother implementation, when a TA Command MAC CE is received by the UEon a particular DL carrier, the UE may only adjust the UL transmissiontiming reference of the UL carrier paired with the DL carrier asindicated in the SI. In yet another implementation, a CIF is included inthe TA Command MAC CE to indicate the UL carrier on which the UE shouldadjust the UL transmission timing reference.

Ninth, one timeAlignmentTimer may be maintained per carrier group. ThetimeAlignmentTimer may be started or restarted at the UE accordingly ina similar fashion as LTE Rel-8/9 when TA Command MAC CE is received forthe carrier group or an RA response is received from the designated DLcarrier (e.g. the DL anchor carrier if the DL anchor carrier is withinthe carrier group) or any DL carriers or any active DL carriers in thecarrier group.

Tenth, when timeAlignmentTimer of a carrier group expires, the UE mayflush all hybrid automatic repeat request (HARQ) buffers associated withthe DL and UL carriers in the carrier group, notify RRC to releasePUCCH/SRS associated with the UL carriers in the carrier group, and/orclear any configured downlink assignments and uplink grants associatedwith the DL and UL carriers in the carrier group.

In another implementation of the present system, a carrier group may notmaintain its UL transmission timing reference and associated timers. Inthat case, the UL transmission timing reference of the UL carriers inthe carrier group may be an offset to the UL transmission timingreference of another carrier group. The offset may be predefined orsignaled by the base station. Alternatively, a carrier group may not useits DL carriers for DL PL estimation to compute the RA preambletransmission power or UL power control of its UL carriers. In that case,the DL carrier(s) (a designated DL carrier or any active DL carriers orany DL carriers) belonging to an associated carrier group may be usedfor these purposes.

Distinguishing a Non-Backward Compatible Rel-10 Carrier from a BackwardCompatible Rel-10 Carrier

In some cases, it may be difficult for a UE to identify non-backwardcompatible CCs. Even though non-backward compatible, some Type A CCs maybe fully accessible to a particular UE. For example, the sync channeland MIB/SIBs of such a Type A CC may be fully backward compatible withversions or releases of the specification prior to the introduction ofcarrier aggregation meaning that a legacy UE might attempt to camp onthe carrier and then access that carrier. For a legacy UE in Idle modethe UE may attempt to read the MIB/SIBs of that CC if the signalstrength is the strongest for that carrier frequency. In that case, thelegacy UE may only find out that it is not permitted to camp or accessthe carrier after reading the SIB2 message received via that CC.

In one implementation of the present system, the idleModeMobilityControlInfo included in the RRCConnectionRelease message indicates the priorityof the cell reselection of a certain carrier frequency. In that case, anon-backward compatible CC may not be assigned a priority. Thisapproach, however, may only work for UEs that have previously enteredRRC_CONNECTED state and may not work for UEs that have recently poweredon. Any CC that is not assigned a priority value may not be consideredby the UE for the purpose of cell reselection. While this can prevent aUE from attempting to reselect to a non backwards compatible CC, it doesnot prevent the UE from attempting to select the non backward compatibleCC at cell selection (for example, when the UE is first switched on, orwhen it is attempting to recover from loss of coverage).

In a second approach, different types of sequences for PCI/PSC aredefined for the non-backward compatible CC so that legacy UEs will notbe able to detect a non-backward compatible CC. This approach has theconstraint that all the neighbor base stations in the network shouldconfigure the same CC frequency as the non-backward compatible CC sothat the legacy UE cell search and measurement will not be affected. Theconstraint of the approach is that the UE may keep trying to decode theMIB until a certain failure criteria is satisfied causing the UE to stopattempting to read the MIB and to consider the cell as barred (i.e. acell that it is not permitted to camp on or access)

In a third approach, a different format (coding rate, payload size etc.)for the MIB is defined on the non-backward compatible CC so that alegacy UE will not be able to decode the MIB and therefore will notproceed to decode other SIBs. After failing to decode the MIB, the UEmay consider the cell as barred.

In a fourth approach, an explicit indication may be included in theSIB1. The existing cell barred indication in SIB1 can be used to preventa legacy UEs from further accessing the cell or CC and reading thesubsequent SI message. The IE intraFreqReselection in SIB1 can also beused to indicate to the UE that all cells in the same frequency arebarred so that UE will not search neighbor base stations fornon-backward compatible CCs if those non-backward compatible CCs havethe same frequency. Because a UE compliant to a release of thespecification that does support carrier aggregation (i.e. a non legacyUE) may need to know that those ‘barred’ cell are accessible such nonlegacy UEs, a new field is added to SIB1 to indicate to the non legacyUEs whether the cell is actually barred for the non legacy UEs. If thenew field is not present in the SI, for example because it is a legacycell that does not support the new field, then the UE may be configuredto operate in accordance with the original cellBarred SI field that waspresent in versions or releases of the specification prior to theintroduction of carrier aggregation. If the new field is present, a nonlegacy UE may ignore the original cellBarred field and only act upon thesetting of the new cellBarred2 field.

Table 7 shows example RRC signaling to provide an indication in SIB1 asto whether the CC is a non-backward compatible CC as described above.Changes with respect to the System InformationBlockType1 specified priorto the version or release in which carrier aggregation was introducedare underlined.

TABLE 7 SystemInformationBlockType1 SystemInformationBlockType1 containsinformation relevant when evaluating if a UE is allowed to access a celland defines the scheduling of other system information. Signalling radiobearer: N/A RLC-SAP: TM Logical channel: BCCH Direction: E-UTRAN to UESystemInformationBlockType1 message         ASN1STARTSystemInformationBlockType1 ::= SEQUENCE {   cellAccessRelatedInfo  SEQUENCE {     plmn-IdentityList     PLMN-IdentityList,    trackingAreaCode     TrackingAreaCode,     cellIdentity    CellIdentity,     cellBarred     ENUMERATED {barred, notBarred},    intraFreqReselection     ENUMERATED {allowed, notAllowed},    csg-Indication     BOOLEAN,     csg-Identity     BIT STRING (SIZE(27)) OPTIONAL -- Need OR   },   cellSelectionInfo   SEQUENCE {    q-RxLevMin     Q-RxLevMin,     q-RxLevMinOffset     INTEGER (1..8)OPTIONAL -- Need OP   },   p-Max   p-Max OPTIONAL,    -- Need OP  freqBandIndicator   INTEGER (1..64),   schedulingInfoList  SchedulingInfoList,   tdd-Config   TDD-Config OPTIONAL, -- Cond TDD  si-WindowLength   ENUMERATED {     ms1, ms2, ms5, ms10, ms15, ms20,    ms40},   systemInfoValueTag   INTEGER (0..31),  nonCriticalExtension   SEQUENCE {     cellBarred2    ENUMERATED {barred, notBarred} OPTIONAL,     nonCriticalExtension    SEQUENCE { } OPTIONAL -- Need OP   }      OPTIONAL -- Need OP }PLMN-IdentityList ::=   SEQUENCE (SIZE (1..6)) OF PLMN-IdentityInfoPLMN-IdentityInfo ::=   SEQUENCE {   plmn-Identity     PLMN-Identity,  cellReservedForOperatorUse     ENUMERATED {reserved, notReserved} }SchedulingInfoList ::= SEQUENCE (SIZE (1..maxSI-Message)) OFSchedulingInfo SchedulingInfo ::= SEQUENCE {   si-Periodicity  ENUMERATED {     rf8, rf16, rf32, rf64, rf128, rf256, rf512},  sib-MappingInfo   SIB-MappingInfo } SIB-MappingInfo ::= SEQUENCE (SIZE(0..maxSIB−1)) OF SIB-Type SIB-Type ::= ENUMERATED {   sibType3,sibType4, sibType5, sibType6,   sibType7, sibType8, sibType9, sibType10,  sibType11, spare7, spare6, spare5,   spare4, spare3, spare2, spare1,...}         ASN1STOP SystemInformationBlockType1 field descriptionsplmn-IdentityList List of PLMN identities. The first listedPLMN-Identity is the primary PLMN. cellReservedForOperatorUse As definedin TS 36.304 [4]. trackingAreaCode A trackingAreaCode that is common forall the PLMNs listed. cellBarred ‘barred’ means the cell is barred, asdefined in TS 36.304 [4]. cellBarred2 If this IE is present then the UEignores the value of cellBarred and acts on the value of cellBarred2.‘barred’ means the cell is barred, as defined in TS 36.304 [4].intraFreqReselection Used to control cell reselection to intra-frequencycells when the highest ranked cell is barred, or treated as barred bythe UE, as specified in TS 36.304 [4]. Csg-Indication If set to TRUE theUE is only allowed to access the cell if the CSG identity matches anentry in the allowed CSG list that the UE has stored. q-RxLevMinOffsetParameter Q_(rxlevminoffset) in 36.304 [4]. Actual valueQ_(rxlevminoffset) = IE value * 2 [dB]. If absent, apply the (default)value of 0 [dB] for Q_(rxlevminoffset). Affects the minimum required Rxlevel in the cell. p-Max Value applicable for the cell.freqBandIndicator Defined in TS 36.101 [42, table 5.5-1]. Si-PeriodicityPeriodicity of the SI-message in radio frames, such that rf8 denotes 8radio frames, rf16 denotes 16 radio frames, and so on. Sib-MappingInfoList of the SIBs mapped to this SystemInformation message.There is nomapping information of SIB2; it is always present in the firstSystemInformation message listed in the schedulingInfoList list.Si-WindowLength Common SI scheduling window for all Sis. Unit inmilliseconds, where ms1 denotes 1 millisecond, ms2 denotes 2milliseconds and so on. systemInfoValueTag Common for all SIBs otherthan MIB, SIB1, SIB10 and SIB11. Csg-Identity Identity of the ClosedSubscriber Group within the primary PLMN the cell belongs to. The IE ispresent in a CSG cell. Conditional presence Explanation TDD This fieldis mandatory present for TDD; it is not present for FDD and the UE shalldelete any existing value for this field.

In a fifth approach, the frequency band indicator contained in an SIB1message may be used to indicate whether a CC is backward compatible. Inthis case, a new frequency band may be defined that may use the samedownlink frequencies as defined for a pre-existing band, but thatsupports a different duplex spacing. A legacy UE would not recognize thenew band which is included in SIB1 and therefore would consider the cellinaccessible.

Generally, different approaches may be used for Type A and Type B CCs.For example, the second approach may be used for a Type B CC if the TypeB CC transmits synchronization signals. If, however, a Type B CC doesnot transmit synchronization signals, a legacy UE may not be able todetect the CC and therefore will not attempt to read the MIB/SIBs of theCC.

Mobility Measurement

In existing network implementations, measurement objects and measurementidentities are configured for a UE by the base station to triggermeasurement reporting from the UE. A measurement object is associatedwith a particular carrier frequency, which may be the same frequency asthe serving cell or a different frequency for the case ofinter-frequency measurement. The base station can configure more thanone measurement objects for a UE. To trigger measurement reporting froma UE, the base station configures one or more measurement identities fora UE. Each measurement identity is associated with a measurement objectand a reporting configuration. A reporting configuration defines thecriteria upon which the measurement reporting from the UE is triggered.Five measurement reporting trigger events (A1 to A5) are defined in 3GPPTS 36.331 V8.6.0 Technical Specification Group Radio Access Network;Evolved Universal Terrestrial Radio Access (E-UTRA); Radio ResourceControl (RRC); Protocol specification (Release 8), June 2009.

In the present system, the base station may configure measurementobjects for all of the CCs in the UE's Active CC set, where onemeasurement object corresponds to one CC frequency. It may not benecessary for a UE to perform mobility measurement on all the active CCssince the channel condition (e.g. RSRP, RSRQ) for CCs within the sameband may be similar. In one implementation, the base station mayconfigure measurement objects for a subset of the CCs in the UE's ActiveCC set. In another implementation, the base station may configuremeasurement objects for all or a subset of the CCs in the UE's CandidateCC set. In yet another implementation, the base station may configure ameasurement object for a carrier which is not in the UE's Candidate CCset. For each configured measurement object that corresponds to aparticular CC frequency, the base station may configure one or moremeasurement identities, each corresponding to a different reportingconfiguration.

The base station may not configure measurement gaps for the UE toperform measurement on a CC which is in the UE's Active CC set since theUE has enabled signal reception on CCs within the UE's Active CC set.The base station may configure measurement gaps for the UE to performmeasurement on a CC which is not in the UE's Active CC set.

When a measurement object corresponds to the carrier frequency of a CCis configured, one or more reporting configuration can be configured forthe measurement object based on one of the following five measurementreporting trigger events (C1 to C6). C1 defines the measurementreporting criteria based on: the signal quality (RSRP or RSRQ) of the CCin the UE's Candidate CC set or Active CC set with carrier frequencycorresponding to the measurement object, better than a configuredthreshold. C2 defines the measurement reporting criteria based on: thesignal quality (RSRP or RSRQ) of the CC in the UE's Candidate CC set orActive CC set with carrier frequency corresponding to the measurementobject, worse than a configured threshold. C3 defines the measurementreporting criteria based on: the signal quality (RSRP or RSRQ) of aneighbor cell, i.e. a non-serving cell or a CC not in the UE's CandidateCC set or Active CC set, on the carrier frequency corresponding to themeasurement object, becomes offset better than the signal quality (RSRPor RSRQ) of the CC in the UE's Candidate CC set or Active CC set withcarrier frequency corresponding to the measurement object. C4 definesthe measurement reporting criteria based on: the signal quality (RSRP orRSRQ) of a neighbor cell on the carrier frequency corresponding to themeasurement object, better than a configured threshold. C5 defines themeasurement reporting criteria based on: the signal quality (RSRP orRSRQ) of the CC in the UE's Candidate CC set or Active CC set withcarrier frequency corresponding to the measurement object, worse than aconfigured threshold1; while the signal quality (RSRP or RSRQ) of aneighbor cell on the carrier frequency corresponding to the measurementobject, better than a configured threshold2. C6 defines the measurementreporting criteria based on: the signal quality (RSRP or RSRQ) of aneighbor cell on the carrier frequency corresponding to the measurementobject, worse than a configured threshold.

Additional measurement reporting trigger events may also be definedbased on a comparison of signal quality (RSRP or RSRQ) between aneighbor cell (i.e. a non-serving cell or a CC not in the UE's CandidateCC set or Active CC set) and one or more CCs in the UE's Candidate CCset or Active CC set. D1 defines the measurement reporting criteriabased on: the signal quality (RSRP or RSRQ) of a neighbor cell, i.e. anon-serving cell or a CC not in the UE's Candidate CC set or Active CCset, on the carrier frequency corresponding to the measurement object,becomes offset better than the signal quality (RSRP or RSRQ) of at leastone of the CC in the list of CCs defined for the measurement identity.The list of CCs are within the UE's Candidate CC set or Active CC set.D2 defines the measurement reporting criteria based on: the signalquality (RSRP or RSRQ) of a neighbor cell on the carrier frequencycorresponding to the measurement object, becomes offset between than thesignal quality (RSRP or RSRQ) of all of the CCs in the list of CCsdefined for the measurement identity. The list of CCs are within theUE's Candidate CC set or Active CC set. D3 defines the measurementreporting criteria based on: the signal quality (RSRP or RSRQ) of atleast one of the CC in the list of CCs defined for the measurementidentity becomes worse than a configured threshold1; while the signalquality (RSRP or RSRQ) of a neighbor cell on the carrier frequencycorresponding to the measurement object, becomes better than aconfigured threshold2. The list of CCs are within the UE's Candidate CCset or Active CC set. D4 defines the measurement reporting criteriabased on: the signal quality (RSRP or RSRQ) of all of the CCs in thelist of CCs defined for the measurement identity becomes worse than aconfigured threshold1; while the signal quality (RSRP or RSRQ) of aneighbor cell on the carrier frequency corresponding to the measurementobject, becomes better than a configured threshold2. The list of CCs arewithin the UE's Candidate CC set or Active CC set.

Further measurement reporting trigger events are also defined based on acomparison of signal quality (RSRP or RSRQ) among CCs within the UE'sCandidate CC set or Active CC set. E1 defines the measurement reportingcriteria based on: the signal quality (RSRP or RSRQ) of a specific CC(which may correspond to the measurement object associated with themeasurement identity) in the UE's Candidate CC set or Active CC setbecomes offset better than the signal quality (RSRP or RSRQ) of at leastone of the CC in the list of CCs defined for the measurement entity. Thelist of CCs may be within the UE's Candidate CC set or Active CC set. E2defines the measurement reporting criteria based on the signal quality(RSRP or RSRQ) of a specific CC (which may correspond to the measurementobject associated with the measurement identity) in the UE's CandidateCC set or Active CC set becomes offset better than the signal quality(RSRP or RSRQ) of all of the CC in the list of CCs defined for themeasurement entity. The list of CCs may be within the UE's Candidate CCset or Active CC set. E3 defines the measurement reporting criteriabased on the signal quality (RSRP or RSRQ) of at least one of the CC inthe list of CCs defined for the measurement identity becomes worse thana first configured threshold1; while the signal quality (RSRP or RSRQ)of a specific CC (which may correspond to the measurement objectassociated with the measurement identity) in the UE's Candidate CC setor Active CC set becomes better than a second configured threshold2. Thelist of CCs are within the UE's Candidate CC set or Active CC set. E4defines the measurement reporting criteria based on the signal quality(RSRP or RSRQ) of all of the CCs in the list of CCs defined for themeasurement identity becomes worse than a first configured threshold1;while the signal quality (RSRP or RSRQ) of a specific CC (which maycorrespond to the measurement object associated with the measurementidentity) in the UE's Candidate CC set or Active CC set becomes betterthan a second configured threshold2. The list of CCs may be within theUE's Candidate CC set or Active CC set.

Radio Link Failure (RLF)

In existing network implementation, RLF is defined as a situation when aUE experiences ‘out-of-sync’ at the DL physical layer for a predefinedduration; or when random access failure is experienced on the UL; orwhen maximum number of retransmissions has been reached at the RadioLink Control (RLC). A UE estimates the DL radio link quality of theserving cell based on the cell-specific reference signal (RS) andcompare it to a threshold Qout. If the radio link quality is below Qout,then the UE experience ‘out-of-sync’. The threshold Qout is defined asthe level at which the DL radio link cannot be reliably received andcorresponds to [10%] block error rate of a hypothetical PDCCHtransmission taking into account the PCFICH errors. When RLF occurs, theUE enters RLF recovery procedure, which includes cell selection and RRCconnection re-establishment.

In the present system, when a UE is assigned multiple CCs in the UE'sActive CC set, RLF may be defined based on the radio link quality ofone, or more or all of the CCs in the UE's Active CC set. A UEexperiencing poor radio link quality on one CC may not experience poorradio link quality on another CC even if they are on the same band. Thisis because the carrier deployments in the network may not be uniformacross base stations. In addition, pico or femto cells that are deployedwithin the coverage area of a macro cell on a certain carrier frequencywill create additional interference on that carrier frequency. For CCson different band, if the UE experiences poor radio link quality on thelower frequency band, it is likely that it will experience poor radiolink quality on the higher frequency band.

In the DL, the connection between the base station and UE is consideredlost when the UE cannot receive any PDCCH transmitted from the basestation for a predefined duration, since neither PDSCH nor PUSCHresource can be allocated to the UE to carry any user plane and controlplane traffic. As previously described, a UE can be assigned one ormultiple DL PDCCH monitoring CCs in the Active CC set. If all DL PDCCHmonitoring carriers experience ‘out-of-sync’ for a predefined duration,or all UL carriers experience random access failure, the UE isconsidered to be in RLF and enters RLF recovery procedure. If at leastone DL PDCCH monitoring CC does not experience ‘out-of-sync’ and atleast one UL carrier does not experience random access failure, the UEis not considered to be in RLF. The UE reports the DL and/or UL radiolink quality situation of the affected carriers to the base stationusing the remaining DL PDCCH monitoring CCs which do not experience‘out-of-sync’ and remaining UL carriers which do not experience randomaccess failure. The base station may re-assign different DL and/or ULCCs to the UE via signaling such as RRC signaling or MAC controlelement.

In one implementation, a DL PDCCH monitoring carrier assigned to the UEis associated with a subset of the UL carriers assigned to the UE. TheDL PDCCH monitoring carrier only sends PUSCH resource assignment for itsassociated UL carriers. Another DL PDCCH monitoring carrier isassociated with another subset of the UL carriers assigned to the UE.RLF occurs when the UE cannot receive PDCCH from the base station thatallocate UL PUSCH resource on any of the UL carriers which do notexperience random access failure. For example, a DL PDCCH monitoringcarrier, C_(DL) _(—) ₁, is associated with the UL carrier, C_(UL) _(—)₁. Another DL PDCCH monitoring carrier, C_(DL) _(—) ₂, is associatedwith another UL carrier, C_(UL) _(—) ₂. When C_(DL) _(—) ₁ experiences‘out-of-sync’ for a predefined duration and C_(UL) _(—) ₂ experiencesrandom access failure, the UE is considered in RLF since C_(DL) _(—) ₂cannot send PDCCH to assign PUSCH on C_(UL) _(—) ₁. In oneimplementation, the base station may detect that a UE is experiencing‘out-of-sync’ on a DL PDCCH monitoring carrier through PDSCH failure onthat carrier. In that case, the base station may transmit signaling tothe UE (e.g. RRC signaling or MAC control element) to re-assign theassociation of UL carriers with the remaining DL PDCCH monitoringcarriers which do not experience ‘out-of-sync’. In anotherimplementation, when the UE detects that a DL PDCCH monitoring carrieris experiencing ‘out-of-sync’ condition for a predefined duration, theUE informs the base station through signaling (RRC signaling or MACcontrol element) on an UL carrier which is associated with a DL PDCCHmonitoring carrier that does not experience ‘out-of-sync’ condition.

In another embodiment, the base station may detect that a UE isexperiencing random access failure on a UL carrier though receivedsignal strength of the random access channel transmitted from the UE. Inthat case, the base station may signal the UE (through RRC signaling orMAC control element) to re-assign the association of remaining ULcarriers with the DL PDCCH monitoring carriers to distribute the numberof UL carriers associated with each DL PDCCH monitoring, or to ensureeach DL PDCCH monitoring carrier has at least on associated UL carrier.

To prevent RLF as described above to occur, the base station mayconfigure a UE to send measurement report on one or more of the CCs inthe UE's Active CC set. The reporting configuration can be set such thatmeasurement reporting from the UE is triggered on a particular CC wellin advance of the occurrence of the ‘out-of-sync’ condition on that CC.In another embodiment, the base station may configure the UE to transmitDL channel quality indicator (CQI) periodically on UL PUCCH or PUSCH.Through monitoring the DL CQI feedback from the UE on a CC, the basestation can estimate when ‘out-of-sync’ condition is likely to occur onthe CC.

When the base station detects that a UE is in poor radio link qualitymay experience ‘out-of-sync’ condition on a CC through the methodsdescribed above, the base station may signal the UE (through RRCsignaling or MAC control element) to de-allocate the CC, i.e. to removethe CC from the UE's Candidate CC set; or to instruct the UE to disablesignal reception on the CC, i.e. to remove the CC from the UE's ActiveCC set. If this CC is a PDCCH monitoring carrier, the base station mayassign another CC as PDCCH monitoring CC for the UE.

In another embodiment, a subset of the DL PDCCH monitoring CCs assignedto the UE are designated as the DL radio link monitoring CC set. Asubset of the UL CCs assigned to the UE are designated as the UL radiolink monitoring CC set. The CCs for these sets may be selected such thatthese CCs can represent other CCs not in the sets in terms of largescale fading (i.e. for other CCs in the same band), and carriers loadingand interference conditions.

If all CCs in the DL radio link monitoring CC set experience‘out-of-sync’ for a predefined duration, or all UL CCs in the UL radiolink monitoring CC set experience random access failure, the UE isconsidered to be in RLF and enters RLF recovery procedure. If at leastone CC in the DL radio link monitoring CC set does not experience‘out-of-sync’ and at least one UL CC in the UL radio link monitoring CCset does not experience random access failure, the UE is not consideredto be in RLF. The UE reports the DL and/or UL radio link qualitysituation of the affected CCs to the base station using the remaining DLPDCCH monitoring CCs which do not experience ‘out-of-sync’ and remainingUL CCs which do not experience random access failure. The base stationmay re-assign different DL and/or UL CCs to the UE and to the UE's DL/ULradio link monitoring CC sets via signaling such as RRC signaling or MACcontrol element.

At any time, if maximum number of retransmissions has been reached atthe RLC, a UE is considered in RLF and RLF recovery process istriggered.

FIG. 6 illustrates a wireless communications system including anembodiment of UA 10. UA 10 is operable for implementing aspects of thedisclosure, but the disclosure should not be limited to theseimplementations. Though illustrated as a mobile phone, the UA 10 maytake various forms including a wireless handset, a pager, a personaldigital assistant (PDA), a portable computer, a tablet computer, alaptop computer. Many suitable devices combine some or all of thesefunctions. In some embodiments of the disclosure, the UA 10 is not ageneral purpose computing device like a portable, laptop or tabletcomputer, but rather is a special-purpose communications device such asa mobile phone, a wireless handset, a pager, a PDA, or atelecommunications device installed in a vehicle. The UA 10 may also bea device, include a device, or be included in a device that has similarcapabilities but that is not transportable, such as a desktop computer,a set-top box, or a network node. The UA 10 may support specializedactivities such as gaming, inventory control, job control, and/or taskmanagement functions, and so on.

The UA 10 includes a display 702. The UA 10 also includes atouch-sensitive surface, a keyboard or other input keys generallyreferred as 704 for input by a user. The keyboard may be a full orreduced alphanumeric keyboard such as QWERTY, Dvorak, AZERTY, andsequential types, or a traditional numeric keypad with alphabet lettersassociated with a telephone keypad. The input keys may include atrackwheel, an exit or escape key, a trackball, and other navigationalor functional keys, which may be inwardly depressed to provide furtherinput function. The UA 10 may present options for the user to select,controls for the user to actuate, and/or cursors or other indicators forthe user to direct.

The UA 10 may further accept data entry from the user, including numbersto dial or various parameter values for configuring the operation of theUA 10. The UA 10 may further execute one or more software or firmwareapplications in response to user commands. These applications mayconfigure the UA 10 to perform various customized functions in responseto user interaction. Additionally, the UA 10 may be programmed and/orconfigured over-the-air, for example from a wireless base station, awireless access point, or a peer UA 10.

Among the various applications executable by the UA 10 are a webbrowser, which enables the display 702 to show a web page. The web pagemay be obtained via wireless communications with a wireless networkaccess node, a cell tower, a peer UA 10, or any other wirelesscommunication network or system 700. The network 700 is coupled to awired network 708, such as the Internet. Via the wireless link and thewired network, the UA 10 has access to information on various servers,such as a server 710. The server 710 may provide content that may beshown on the display 702. Alternately, the UA 10 may access the network700 through a peer UA 10 acting as an intermediary, in a relay type orhop type of connection.

FIG. 7 shows a block diagram of the UA 10. While a variety of knowncomponents of UAs 110 are depicted, in an embodiment a subset of thelisted components and/or additional components not listed may beincluded in the UA 10. The UA 10 includes a digital signal processor(DSP) 802 and a memory 804. As shown, the UA 10 may further include anantenna and front end unit 806, a radio frequency (RF) transceiver 808,an analog baseband processing unit 810, a microphone 812, an earpiecespeaker 814, a headset port 816, an input/output interface 818, aremovable memory card 820, a universal serial bus (USB) port 822, ashort range wireless communication sub-system 824, an alert 826, akeypad 828, a liquid crystal display (LCD), which may include a touchsensitive surface 830, an LCD controller 832, a charge-coupled device(CCD) camera 834, a camera controller 836, and a global positioningsystem (GPS) sensor 838. In an embodiment, the UA 10 may include anotherkind of display that does not provide a touch sensitive screen. In anembodiment, the DSP 802 may communicate directly with the memory 804without passing through the input/output interface 818.

The DSP 802 or some other form of controller or central processing unitoperates to control the various components of the UA 10 in accordancewith embedded software or firmware stored in memory 804 or stored inmemory contained within the DSP 802 itself. In addition to the embeddedsoftware or firmware, the DSP 802 may execute other applications storedin the memory 804 or made available via information carrier media suchas portable data storage media like the removable memory card 820 or viawired or wireless network communications. The application software maycomprise a compiled set of machine-readable instructions that configurethe DSP 802 to provide the desired functionality, or the applicationsoftware may be high-level software instructions to be processed by aninterpreter or compiler to indirectly configure the DSP 802.

The antenna and front end unit 806 may be provided to convert betweenwireless signals and electrical signals, enabling the UA 10 to send andreceive information from a cellular network or some other availablewireless communications network or from a peer UA 10. In an embodiment,the antenna and front end unit 806 may include multiple antennas tosupport beam forming and/or multiple input multiple output (MIMO)operations. As is known to those skilled in the art, MIMO operations mayprovide spatial diversity which can be used to overcome difficultchannel conditions and/or increase channel throughput. The antenna andfront end unit 806 may include antenna tuning and/or impedance matchingcomponents, RF power amplifiers, and/or low noise amplifiers.

The RF transceiver 808 provides frequency shifting, converting receivedRF signals to baseband and converting baseband transmit signals to RF.In some descriptions a radio transceiver or RF transceiver may beunderstood to include other signal processing functionality such asmodulation/demodulation, coding/decoding, interleaving/deinterleaving,spreading/despreading, inverse fast Fourier transforming (IFFT)/fastFourier transforming (FFT), cyclic prefix appending/removal, and othersignal processing functions. For the purposes of clarity, thedescription here separates the description of this signal processingfrom the RF and/or radio stage and conceptually allocates that signalprocessing to the analog baseband processing unit 810 and/or the DSP 802or other central processing unit. In some embodiments, the RFTransceiver 808, portions of the Antenna and Front End 806, and theanalog base band processing unit 810 may be combined in one or moreprocessing units and/or application specific integrated circuits(ASICs).

The analog baseband processing unit 810 may provide various analogprocessing of inputs and outputs, for example analog processing ofinputs from the microphone 812 and the headset 816 and outputs to theearpiece 814 and the headset 816. To that end, the analog basebandprocessing unit 810 may have ports for connecting to the built-inmicrophone 812 and the earpiece speaker 814 that enable the UA 10 to beused as a cell phone. The analog baseband processing unit 810 mayfurther include a port for connecting to a headset or other hands-freemicrophone and speaker configuration. The analog baseband processingunit 810 may provide digital-to-analog conversion in one signaldirection and analog-to-digital conversion in the opposing signaldirection. In some embodiments, at least some of the functionality ofthe analog baseband processing unit 810 may be provided by digitalprocessing components, for example by the DSP 802 or by other centralprocessing units.

The DSP 802 may perform modulation/demodulation, coding/decoding,interleaving/deinterleaving, spreading/despreading, inverse fast Fouriertransforming (IFFT)/fast Fourier transforming (FFT), cyclic prefixappending/removal, and other signal processing functions associated withwireless communications. In an embodiment, for example in a codedivision multiple access (CDMA) technology application, for atransmitter function the DSP 802 may perform modulation, coding,interleaving, and spreading, and for a receiver function the DSP 802 mayperform despreading, deinterleaving, decoding, and demodulation. Inanother embodiment, for example in an orthogonal frequency divisionmultiplex access (OFDMA) technology application, for the transmitterfunction the DSP 802 may perform modulation, coding, interleaving,inverse fast Fourier transforming, and cyclic prefix appending, and fora receiver function the DSP 802 may perform cyclic prefix removal, fastFourier transforming, deinterleaving, decoding, and demodulation. Inother wireless technology applications, yet other signal processingfunctions and combinations of signal processing functions may beperformed by the DSP 802.

The DSP 802 may communicate with a wireless network via the analogbaseband processing unit 810. In some embodiments, the communication mayprovide Internet connectivity, enabling a user to gain access to contenton the Internet and to send and receive e-mail or text messages. Theinput/output interface 818 interconnects the DSP 802 and variousmemories and interfaces. The memory 804 and the removable memory card820 may provide software and data to configure the operation of the DSP802. Among the interfaces may be the USB interface 822 and the shortrange wireless communication sub-system 824. The USB interface 822 maybe used to charge the UA 10 and may also enable the UA 10 to function asa peripheral device to exchange information with a personal computer orother computer system. The short range wireless communication sub-system824 may include an infrared port, a Bluetooth interface, an IEEE 802.11compliant wireless interface, or any other short range wirelesscommunication sub-system, which may enable the UA 10 to communicatewirelessly with other nearby mobile devices and/or wireless basestations.

The input/output interface 818 may further connect the DSP 802 to thealert 826 that, when triggered, causes the UA 10 to provide a notice tothe user, for example, by ringing, playing a melody, or vibrating. Thealert 826 may serve as a mechanism for alerting the user to any ofvarious events such as an incoming call, a new text message, and anappointment reminder by silently vibrating, or by playing a specificpre-assigned melody for a particular caller.

The keypad 828 couples to the DSP 802 via the interface 818 to provideone mechanism for the user to make selections, enter information, andotherwise provide input to the UA 10. The keyboard 828 may be a full orreduced alphanumeric keyboard such as QWERTY, Dvorak, AZERTY andsequential types, or a traditional numeric keypad with alphabet lettersassociated with a telephone keypad. The input keys may include atrackwheel, an exit or escape key, a trackball, and other navigationalor functional keys, which may be inwardly depressed to provide furtherinput function. Another input mechanism may be the LCD 830, which mayinclude touch screen capability and also display text and/or graphics tothe user. The LCD controller 832 couples the DSP 802 to the LCD 830.

The CCD camera 834, if equipped, enables the UA 10 to take digitalpictures. The DSP 802 communicates with the CCD camera 834 via thecamera controller 836. In another embodiment, a camera operatingaccording to a technology other than Charge Coupled Device cameras maybe employed. The GPS sensor 838 is coupled to the DSP 802 to decodeglobal positioning system signals, thereby enabling the UA 10 todetermine its position. Various other peripherals may also be includedto provide additional functions, e.g., radio and television reception.

FIG. 8 illustrates a software environment 902 that may be implemented bythe DSP 802. The DSP 802 executes operating system drivers 904 thatprovide a platform from which the rest of the software operates. Theoperating system drivers 904 provide drivers for the UA hardware withstandardized interfaces that are accessible to application software. Theoperating system drivers 904 include application management services(AMS) 906 that transfer control between applications running on the UA10. Also shown in FIG. 8 are a web browser application 908, a mediaplayer application 910, and Java applets 912. The web browserapplication 908 configures the UA 10 to operate as a web browser,allowing a user to enter information into forms and select links toretrieve and view web pages. The media player application 910 configuresthe UA 10 to retrieve and play audio or audiovisual media. The Javaapplets 912 configure the UA 10 to provide games, utilities, and otherfunctionality. A component 914 might provide functionality describedherein.

The UA 10, base station 120, and other components described above mightinclude a processing component that is capable of executing instructionsrelated to the actions described above. FIG. 9 illustrates an example ofa system 1000 that includes a processing component 1010 suitable forimplementing one or more embodiments disclosed herein. In addition tothe processor 1010 (which may be referred to as a central processor unit(CPU or DSP), the system 1000 might include network connectivity devices1020, random access memory (RAM) 1030, read only memory (ROM) 1040,secondary storage 1050, and input/output (I/O) devices 1060. In somecases, some of these components may not be present or may be combined invarious combinations with one another or with other components notshown. These components might be located in a single physical entity orin more than one physical entity. Any actions described herein as beingtaken by the processor 1010 might be taken by the processor 1010 aloneor by the processor 1010 in conjunction with one or more componentsshown or not shown in the drawing.

The processor 1010 executes instructions, codes, computer programs, orscripts that it might access from the network connectivity devices 1020,RAM 1030, ROM 1040, or secondary storage 1050 (which might includevarious disk-based systems such as hard disk, floppy disk, or opticaldisk). While only one processor 1010 is shown, multiple processors maybe present. Thus, while instructions may be discussed as being executedby a processor, the instructions may be executed simultaneously,serially, or otherwise by one or multiple processors. The processor 1010may be implemented as one or more CPU chips.

The network connectivity devices 1020 may take the form of modems, modembanks, Ethernet devices, universal serial bus (USB) interface devices,serial interfaces, token ring devices, fiber distributed data interface(FDDI) devices, wireless local area network (WLAN) devices, radiotransceiver devices such as code division multiple access (CDMA)devices, global system for mobile communications (GSM) radio transceiverdevices, worldwide interoperability for microwave access (WiMAX)devices, and/or other well-known devices for connecting to networks.These network connectivity devices 1020 may enable the processor 1010 tocommunicate with the Internet or one or more telecommunications networksor other networks from which the processor 1010 might receiveinformation or to which the processor 1010 might output information.

The network connectivity devices 1020 might also include one or moretransceiver components 1025 capable of transmitting and/or receivingdata wirelessly in the form of electromagnetic waves, such as radiofrequency signals or microwave frequency signals. Alternatively, thedata may propagate in or on the surface of electrical conductors, incoaxial cables, in waveguides, in optical media such as optical fiber,or in other media. The transceiver component 1025 might include separatereceiving and transmitting units or a single transceiver. Informationtransmitted or received by the transceiver 1025 may include data thathas been processed by the processor 1010 or instructions that are to beexecuted by processor 1010. Such information may be received from andoutputted to a network in the form, for example, of a computer databaseband signal or signal embodied in a carrier wave. The data may beordered according to different sequences as may be desirable for eitherprocessing or generating the data or transmitting or receiving the data.The baseband signal, the signal embedded in the carrier wave, or othertypes of signals currently used or hereafter developed may be referredto as the transmission medium and may be generated according to severalmethods well known to one skilled in the art.

The RAM 1030 might be used to store volatile data and perhaps to storeinstructions that are executed by the processor 1010. The ROM 1040 is anon-volatile memory device that typically has a smaller memory capacitythan the memory capacity of the secondary storage 1050. ROM 1040 mightbe used to store instructions and perhaps data that are read duringexecution of the instructions. Access to both RAM 1030 and ROM 1040 istypically faster than to secondary storage 1050. The secondary storage1050 is typically comprised of one or more disk drives or tape drivesand might be used for non-volatile storage of data or as an over-flowdata storage device if RAM 1030 is not large enough to hold all workingdata. Secondary storage 1050 may be used to store programs that areloaded into RAM 1030 when such programs are selected for execution.

The I/O devices 1060 may include liquid crystal displays (LCDs), touchscreen displays, keyboards, keypads, switches, dials, mice, track balls,voice recognizers, card readers, paper tape readers, printers, videomonitors, or other well-known input/output devices. Also, thetransceiver 1025 might be considered to be a component of the I/Odevices 1060 instead of or in addition to being a component of thenetwork connectivity devices 1020. Some or all of the I/O devices 1060may be substantially similar to various components depicted in thepreviously described drawing of the UA 10, such as the display 702 andthe input 704.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods may beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

Also, techniques, systems, subsystems and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component, whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and may be made without departing from the spirit and scopedisclosed herein.

To apprise the public of the scope of this invention, the followingclaims are made:

1. A method of pairing and linking carriers in a multi-carrier network,wherein the multi-carrier network includes a downlink carrier, a firstuplink carrier, and a second uplink carrier between a base station and auser equipment (“UE”), comprising: receiving a Radio Resource Control(“RRC”) signaling; pairing the first uplink carrier with the downlinkcarrier using information in said RRC signaling, wherein saidinformation includes the pairing of the downlink carrier with the firstuplink carrier; and linking the second uplink carrier with the downlinkcarrier using information in said RRC signaling, wherein saidinformation includes the linking of the downlink carrier with the seconduplink carrier.
 2. The method of claim 1, wherein at least one of thedownlink carrier and the first uplink carrier is a cell.
 3. The methodof claim 1, wherein said information in said RRC signaling associatedwith pairing the first uplink carrier with the downlink carrier isincluded in a system information (“SI”), wherein said SI is associatedwith at least one of the downlink carrier and the first uplink carrier.4. A method of pairing and linking carriers in a multi-carrier network,wherein the multi-carrier network includes a first downlink carrier, asecond downlink carrier, and an uplink carrier between a base stationand a user equipment (“UE”), comprising: receiving a Radio ResourceControl (“RRC”) signaling; pairing the uplink carrier with the firstdownlink carrier using information in said RRC signaling, wherein saidinformation includes the pairing of the first downlink carrier with theuplink carrier; and linking the uplink carrier with the second downlinkcarrier using information in said RRC signaling, wherein saidinformation includes the linking of the second downlink carrier with theuplink carrier.
 5. The method of claim 4, wherein at least one of thefirst downlink carrier and the uplink carrier is a cell.
 6. The methodof claim 4, wherein said information in said RRC signaling associatedwith said pairing the uplink carrier with the first downlink carrier isincluded in a system information (“SI”), wherein said SI is associatedwith at least one of the first downlink carrier and the uplink carrier.7. The method of claim 4, wherein said information in said RRC signalingassociated with said linking of the second downlink carrier with theuplink carrier includes a criteria for using the second downlink carrierfor assigning a data channel resource on the uplink carrier.
 8. Themethod of claim 7, wherein said criteria includes at least one of thesecond downlink carrier is active, the first downlink carrier is notactive, and the second downlink carrier is higher priority than thefirst downlink carrier.
 9. A method of linking carriers in amulti-carrier network, wherein the multi-carrier network includes afirst downlink carrier, a second downlink carrier, and a third downlinkcarrier between a base station and a user equipment (“UE”), comprising:receiving a Radio Resource Control (“RRC”) signaling; linking the firstdownlink carrier with the second downlink carrier using information insaid RRC signaling, wherein said information includes the linking of thefirst downlink carrier with the second downlink carrier; and linking thefirst downlink carrier with the third downlink carrier using informationin said RRC signaling, wherein said information includes the linking ofthe first downlink carrier with the third downlink carrier.
 10. Themethod of claim 9, wherein said information in said RRC signalingassociated with said linking the first downlink carrier with the seconddownlink carrier includes a criteria for using the second downlinkcarrier to assign a data channel resource on the first downlink carrier.11. The method of claim 10, wherein said criteria includes at least oneof the second downlink carrier is active, the third downlink carrier isnot active, and the second downlink carrier is higher priority than thethird downlink carrier.
 12. The method of claim 9, wherein saidinformation in said RRC signaling associated with said linking the firstdownlink carrier with the third downlink carrier includes a criteria forusing the third downlink carrier to assign a data channel resource onthe first downlink carrier.
 13. The method of claim 12, wherein saidcriteria includes at least one of the third downlink carrier is active,the second downlink carrier is not active, and the third downlinkcarrier is higher priority than the second downlink carrier.
 14. Amethod of assigning a carrier group in a multi-carrier network, whereinthe multi-carrier network includes one or more downlink carriers and oneor more uplink carriers between a base station and a user equipment(“UE”), comprising: determining a propagation metric for each of the oneor more downlink carriers and each of the one or more uplink carriers;grouping each of the one or more downlink carriers and each of the oneor more uplink carriers having about the same said propagation metric toform the carrier group; and sending the carrier group information. 15.The method of claim 14, wherein at least one of the one or more downlinkcarriers and one of the one or more uplink carriers is a cell.
 16. Themethod of claim 14, further comprising: pairing the one or more downlinkcarriers in the carrier group with the one or more uplink carriers inthe carrier group.
 17. The method of claim 14, further comprising:pairing the one or more downlink carriers in the carrier group with theone or more uplink carriers in another carrier group.
 18. The method ofclaim 14, wherein said propagation metric includes at least one of apath loss (“PL”) and a propagation delay (“PD”).
 19. A method ofassigning a carrier group in a multi-carrier network, wherein the multicarrier network includes one or more downlink carriers between a basestation and a user equipment (“UE”), comprising: determining apropagation metric for each of the one or more downlink carriers;grouping each of the one or more downlink carriers having about the samesaid propagation metric to form the carrier group; and sending thecarrier group information.
 20. The method of claim 19, wherein saidpropagation metric includes at least one of a path loss (“PL”) and apropagation delay (“PD”).
 21. A method of assigning a carrier group in amulti-carrier network, wherein the multi-carrier network includes one ormore uplink carriers between a base station and a user equipment (“UE”),comprising: determining a propagation metric for each of the one or moreuplink carriers; grouping each of the one or more uplink carriers havingabout the same said propagation metric to form the carrier group; andsending the carrier group information.
 22. The method of claim 21,wherein said propagation metric includes at least one of a path loss(“PL”) and a propagation delay (“PD”).
 23. A Method of performing arandom access (“RA”) procedure in a multi-carrier network, wherein themulti-carrier network includes a carrier group associated with a basestation and a user equipment (“UE”), wherein said carrier group includesone or more downlink carriers and one or more uplink carriers,comprising: receiving a set of RA parameters of the carrier group;transmitting an RA preamble signal on at least one uplink carrier in thecarrier group using said set of RA parameters; and receiving an RAresponse signal on at least one downlink carrier in the carrier group,wherein said RA response signal corresponds to said RA preamble signal.24. The method of claim 23, wherein at least one of the one or moredownlink carriers and one of the one or more uplink carriers is a cell.25. The method of claim 23, wherein said transmitting an RA preamblesignal on the at least one uplink carrier using said set of RAparameters includes transmitting only one RA preamble signal at any onetime on the uplink carrier.
 26. The method of claim 23, wherein at leastone of the one or more uplink carriers is paired, linked, or both withat least one of the one or more downlink carriers.
 27. The method ofclaim 23, wherein at least one of the one or more uplink carriers is adesignated uplink carrier.
 28. The method of claim 23, wherein at leastone of the one or more downlink carriers is a designated downlinkcarrier.
 29. The method of claim 23, wherein at least one of the one ormore uplink carriers is an uplink anchor carrier.
 30. The method ofclaim 23, wherein at least one of the one or more downlink carriers is adownlink anchor carrier.
 31. The method of claim 23, wherein at leastone of the one or more uplink carriers includes a Physical Random AccessChannel (“PRACH”).
 32. The method of claim 23, wherein said set of RAparameters includes at least one of a timer parameter, a counterparameter, and a transmit power parameter.
 33. The method of claim 23,wherein the multi-carrier network includes another carrier groupassociated with the base station and the UE, wherein said other carriergroup includes one or more other downlink carriers and one or more otheruplink carriers, further comprising: maintaining another set of RAparameters of said other carrier group; transmitting another RA preamblesignal on said one or more other uplink carriers using said other set ofRA parameters; and receiving another RA response signal on said one ormore other downlink carriers, wherein said other RA response signalcorresponds to said other RA preamble signal.
 34. The method of claim33, wherein said transmitting another. RA preamble signal on said one ormore other uplink carriers using said other set of RA parametersincludes transmitting only one said other RA preamble signal at any onetime on said one or more other uplink carriers.
 35. The method of claim33, wherein said RA preamble signal and said other RA preamble signalare independently transmitted.
 36. The method of claim 33, wherein atleast one of said one or more other uplink carriers is paired, linked,or both to at least one of said one or more other downlink carriers. 37.The method of claim 33, wherein said one or more other uplink carriersis a designated uplink carrier.
 38. The method of claim 33, wherein saidone or more other downlink carriers is a designated downlink carrier.39. The method of claim 33, wherein at least one of the one or moreother uplink carriers is an uplink anchor carrier.
 40. The method ofclaim 33, wherein at least one of the one or more other downlinkcarriers is a downlink anchor carrier.
 41. The method of claim 33,wherein at least one of the one or more other uplink carriers includes aPhysical. Random Access Channel (“PRACH”).
 42. The method of claim 33,wherein said other set of RA parameters includes at least one of a timerparameter, a counter parameter, and a transmit power parameter.